A house is being built behind me and in excavating the foundation they struck rock (shale) in one corner. A hammer on an excavator ran for 4 days straight, then I went to take a look. I was surprised at the small amount of rock that actually had been removed considering the length of time the hammer worked. I've been on jobs that were blasted, and I'm pretty sure this same job could have been done in a half day with blasting. I don't know the cost of blasting, but an excavator with hammer goes for over $200/hr around here, and this guy worked four 9 hour days. I thought it might be interesting to compare the two techniques of removing rock. At what point is it more economical to blast over hammering?
Well I would think that just being in the corner would justify the hammer. Costs of blasting really get up in price on small jobs because there are some set costs whether the job is big or small. The blaster has to have permits and I think (could be wrong) that the contractor has to get permits with the county or city too. Then you have to have dust and noise suppression. Most laws require neighbors to be notified at a certain time period before the blasting will occur and if you have structures close to the blast site then you would have to provide protection for them too. I'm sure there is liability if a structure was damaged, due to vibration among other things, that the contractor would be responsible for. I could see it costing less on a small job if it was a rural area. You would have less to protect and noise and dust might not be such a problem. It was mentioned in another thread that an alternative to hammering and blasting could be something like expanding concrete (not sure of the correct name) poured into drilled holes. This would take care of noise and dust but would take more time. I'm not sure how much of this the blaster would handle but I'm sure that the contractor assumes alot of responsibility of having these safeguards in place. All this barring mass blasting for mines and such because then the price really jumps with the BIG booms. :yup
Countryboy is pretty right from what I know. In mining they'll do anything to blast rather than use machines because its cheaper but residential is another whole kettle of fish: That said a mate of mine works in his brothers blasting business and they make very good money importing special low shatter/slow expanding explosives from South Africa...for exactly the situation you describe. I have seen video of them busting up huge boulders not 20 feet from one of the world's biggest conveyor belts...while it is still operational. I guess its a matter of economics...every site presents its own problems but I know these new high tech explosives are making in-roads in this area.
It largely depends on the conditions and types of rock. For something like a basement, its most cost effective (in the conditions out here) to blast. When a hammer works, it really needs an excavator with a bucket (and ideally, a ripper shank) to work directly with it to be most effective. That adds to costs and is still fairly slow. The subcontractor that's digging basements on the project I'm working on is blasting each one. They broke a tooth off of their 345C's bucket and then wore out two ripper teeth on a excavator ripper shank after digging two basements, so they elected to blast the rest. :thumbsup Generally, if the total amount of rock that needs to be broken/removed is much more than 20 cubic yards; drill it and blast it. The blasting company that blasts for the outfit I work for routinely blasts basements in residential areas, sometimes drilling blast holes within 5' of existing foundations for directional blasts. I've also seen trenchers with rock-hog attachments used to bore out basements in rock. It's faster than a hammer and doesn't require the permits that blasting does. The downside is that rock-hogs require a lot of maintenance and operators who are willing to keep a close eye on the machine so they don't damage or ruin the frog. I don't know what blasting costs are in your area Steve, but it sounds to me like it would have been more cost effective to have called a blaster when they hit the shale and had the problem solved much faster than 4 days with a hammer.
That was my thought too Mass-X. I worked for a company that had a rock drill and did the drilling for the blasters on the jobs we contracted. I was around it enough to be able to give my time estimate on the drilling. I'm in a fairly rural area and we don't have an excessive amount of regulation, but there may be permits required for blasting. I guess the other problem is there aren't a whole lot of companies that do it. I think the pile of shale they excavated is 25 to 30 yds.
If he was hammering shale and it took him that long, then he prolly doesn't know what he is doing. Shale has tons of seams and is very easy to hammer. I've hammered alot of rock around here that came out like white powered, very tough stuff.
Here in NJ there are certain towns NO BLASTING IS ALLOWED !!! But where you can blast you have to have all the permits from the town and county wich take time. You have to have a blasting lisence, you have to pull a $100,000.00 bond to get the blasting permit for each site, you have to hire a surveyor to survey all the surronding homes or buildings around the blast site before and after blasting, you have to have siesmec montering while blasting. It is usally around a $100.00 a CY to blast and there are min. for the blasting company to come in. And most guys get $2,500.00 fee to come in and $2,500.00 to leave. That why I can come in and drill and split for the same price or cheaper with out all the permits and BS.
How big was the hammer Steve?. I know from a number of disgruntled clients that they often get talked into a hammer job by an operator with a way undersize machine for the job. The bigger the better usually. I also know of some operators who have poor hydraulic pressure to their hammers and the hammers are worn out. The thing is there Tap tap tapping away hardly making an impression...its embarrassing but they don't care cause its all hourly hire stuff.
I think somebody running the hammer didn't know what they are doing the contractor I worked for has a hammer on a 690 Deere it can bust up quite abit in a day. The rock in B.C is very hard when you run a hammer it creates a fine white dust it takes awhile to get chunks breaking off. Blasting is very expensive but if you have a big area to blast or a big nub of rock to take off blasting might be cheaper. For a blaster to do a 8 hour job and depending on the job it could cost 4 grand. There are many other options like splitting etc doing blasting in a city neighbourhood might be frowned on. In residential areas like here you need to have blasting mats to keep flying debris to a minimum then you need to blow the whistle to warn a blast is in the process. In a city situation I can see you having to worry about cracking a neighbours foundation.
The machine was a Kobelco, and looking at their website I think it was a ED150 which is a 35,000 lb machine. The site is far enough away I couldn't really see the machine at work, but I heard the hammer going all that time. I was surprised to see the small amount of rock that was moved after all that work. I just remember working around the business, with our company it was no big deal to move in a compressor and drill. We could be set up and drilling within 1/2 hour of pulling in to the job.
Blasting is a skill that doesn't come cheap .. particularly when you're operating in highly populated areas, with adjacent housing. The blasting contractor has to have exceptional skills .. use small charges (read - time consuming) .. use blasting mats, to prevent flyrock .. control access whilst blasting is being undertaken .. and be able to sooth worried and snarly owners in the vicinity. All of this takes time and $$ .. then you add in .. high insurance premiums for the blasting contractor , to cover claims against him, for damage (and a teensy little crack in a wall, is all that's needed for a mega-$$ lawsuit, from litigious neighbors) .. and a hammer looks like a real good option. Even on the mines, oversize rock is oftne busted up with hammer, rather than employ blasting contractors to break them down to fit in the crusher. The cost of a machine with a hammer and a good operator, is far lower than drill and blast on individual big rocks. The guy working on the house behind you, sounds like he needs a bigger machine, with a larger hammer .. or a new operator. 4 days to bust up some shale indicates too small a machine and hammer .. or a poor operator. There's plenty of the latter problem about ..
It sounds like poor operator a hammer on a 16 ton machine should have done alteast 12 yards worth of rock in 8 hours. I meantioned it before but one of the familly friends owns a excavation company the hammer he has cost well over 100 grand but it can split a rock the size of a 4 door sedan in couple hits being its a 12,000ftlb breaker. Dad and I used to do blasting its no big deal you just need to be carefull the dynamite isn't dangerous its the blasting cap that will remove your hand or fingers Thought about going for a blasting ticket there is a demand for power monkeys.
Sounds like either the operator didnt know what he was doing or the breaker wasnt set up right. we have rented a 300 size machine with a breaker before and the damn thing wasnt much better than our backhoe breaker.
I agree with mass X, it depends a lot on a job by job bias. We just had some blasting on one of my jobs. I hit the rock in an industrial park with residential across the street. IIRC there was no notifications the closest building was 100yds. way, it was ~100yds. of rock and it just going to be a quick pop a one day if that job. All I did for prep was push and track 3' of cover on the rock. I sure some of it was the operator, but there are no bets when hammering a vain of rock it take days or weeks with a good operator.
I looked at the machine today and it is indeed a Kobelco ED150 and was fitted with a Promove 24 hammer. The hammer itself looks to be about 6" in diameter. I'm not at all impressed with what I've been seeing on this job thus far. Inside the garage they didn't even peel the topsoil off and today they backfilled the garage over the topsoil.. Now it's been 25°F or less for a couple weeks now and everything is frozen hard, including their spoils pile and the raised the floor of the garage about 2' today with the spoils which are mostly clay. They used something with rubber tires to do some half assed compaction with, but it sure was soft. The soil was spongy even to walk on. They installed footing drains around the foundation, but there are so many chunks of spoils laying in the ditch with the pipe now that I'm pretty certain there will be a flow restriction from it. No stone has been added yet. I get frustrated when I see cobbed up work, I'm a contractor too and it puts the public on guard to be screwed by the next guy when they've been screwed by one already.
I couldn't even find that brand on the net so it must be some odd ball hammer. I wasn't a big beleiver in a hammer untill I got to use one a little bit and see one up close in action. They do have their place and you need a person that knows what they are doing. Have one operator in the area he has well over 10,000 hours running hammer. He said the maintenance on the hammer is important like the nitrogen charge that is inside the hammer which I never knew hammers had. As for one contractor in the apple basket spoiling the rest is true. Contractors that do shoddy work get away with it too but eventually it will catch up to them unless they move to another area.
Come visit here and meet a few jackasses,they'll make your head spin. On the west side they are developing a huge subdivision,well they dug the excavation and poured the foundation...came back 2 days later and stripped the forms and started backfilling with spoil which was mostly clay.Well for compaction he ran his 210 Kobelco excavator around the walls but on the street side he pushed in the foundation wall and cracked it causing a cave in. They pulled away and by the grace of God the homeowner droped in fer a peek,I understood he flipped and called the home builder and told them to fix it,after a month of threats of lawsuits they returned to do a mickey mouse repair of acoustic sealent and 1x3 strapping while the excavator pulled back on the caved in wall.Home owner returned again and flipped and finally got his money back and canceled his loan.I laugh as a new person has took over the home from this builder and the basement keeps rearing its ugly head through leaks since the foundation was never waterproofed and no drainage on the property. I don't understand on how some contractors can sleep at night and give the rest a bad name.
Murray I don't know if you watch the Holmes on Homes show but it seems to be the same in the building trade. We are lucky all the contractors be it excavation to landscapers all care about the job they do. I imagine Vancouver is seeing the slap them up quick get them sold contractors. The houses here are being built for retired people they most likely be in the houses till they croak so build them good so they will last 20-30 years.
I'd imagine everywhere is different but where I work we no longer do secondary blasting unless the chunk is too big to pull out of the panel by the scoop or the chute is plugged. We run a BTI rock breaker. Has an air conditioned cab. http://www.rockbreaker.com/products/mobile/default.htm
I watch the odd Mike Holmes episode but nothing to do with excavating so far though I've been told he did 1 with drain tile and I'd like to catch that and see how he did it.
There was a few shows on doing drain tile and the company that has done all the jobs did all the digging by hand :dizzy I'am glad I don't have that job your digging 7 feet down around the perimeter of the house about the width of your body trench. There was a few shows of him running a rental kubota mini ex.
Steve--I've done some rock work in your part of the world and will say what might at first appear as shale with seams,it literally goes downhill from there.I have seen gravel,clay,hardpan,and ledge all on the same lot up by you.It's real strange up there and I do remember hitting some hard limestone mixed with the shale.This is probably why that hammer took so long.
This project continues, and continues to amuse me. The excavator and a D4 sized Komatsu dozer have been working all week there. For the life of me I can't figure out what they are trying to accomplish. The area they are working on is about 1/2 acre and all the roughing in work was done months ago. The trees have their foliage now so my view is restricted, but I can hear both the dozer and the excavator going back and forth, back and forth all day long! I think the excavator spends more time traveling than digging from what I'm hearing. Somebody's getting a hosing!
Yeah there are some shotty contractors out there. I had one contractor actually ask me which way the holes go on perforated pipe. I thought he was joking. He said he put the holes up to catch any water coming down. I just about fell over laughing! I told him that the holes went down and he didn't believe me. Can you imagine the water that is sitting at the bottom of his footing's just because it has to rise almost 4 inches before it gets to the holes on the pipe. The only thing I can say is that when all the people that chose him because he was cheaper have problem's with water in basement I hope they come to me so I can say I told you so, cause I warned them about his work.
Speaking of holes in pipe I just ran into this on a job I am doing this week. SDR35 perforated pipe has two rows of holes that you face down in a leach field application. I am using the pipe for a foundation application so I opted to use the sewer and drain pipe that has holes around the complete radius of pipe. I wanted use rigid pipe instead of flexible so went this route. The SDR 35 is heavier pipe (cost more) but now that you bring it up, and I thought about it and it would have worked just the same with the holes facing down as pipe with holes around the complete radius. Any arguments for either pipe one way or the other?
I have to disagree with the holes down on drain tile around a basement. I have always put the holes facing up for the reason it does catch the water that comes down the face of the foundation wall - which is where the water infiltrates unless you have an underground spring. You should have clean gravel placed under and over the drain pipe around a basement. Furthermore the pipe and gravel should be at the footing level which is well below the slab level. 6" of crushed stone and 4" of concrete slab in the basement gives you at least 10" above the footing. If you leave the holes on the bottom how do you expect water to collect and flow down the pipe? Any water that collects on the uphill side just runs down the pipe and out the closest set of holes turned down into the gravel. You still get water accumilating until it fills up the gravel trench and the pipe so it can flow out.:beatsme My experience has shown that the gravel with filter fabric carries more water than the pipe. There always seems to be more water seeping out of the gravel at the end of a drain than the pipe. If you were installing a septic system you would want the holes to face down in the trench - since you want the water to infiltrate the ground so the system can work correctly. A basement drain and a septic system are two different systems that do the opposite of each other. The basement drain collects water around the basement and carries it away. A septic system takes water to the ground to disperse it.
CM I wouldn't put holes up on a engineered job they will make you change it. Furthurmore the holes are not directly on the bottom they are a 1/4 way up on each side leaving a trough for the water to go down. The purpose of a perimeter drain is to get underground water not surface. If your trying to collect surface water with a perimiter drain then your grade is wrong around house. Ask any engineer or experienced excavater and they will tell you holes down. As for flexible over rigid , I like the rigid just for it's durability. They both work well.
Think about this. Water follows the path of least resistance. Period. The only reason you need pipe at all is that it provides a 4" diameter conduit of empty space for water to follow. When there's so little water that it can all flow through the gravel, it won't ever enter the pipe, no matter what type it is or which way the holes face. But, when you have a lot of water flowing, the pipe provides sufficient space for a lot of it to flow with much less resistance than if you used gravel alone. Water can move mountains, but it ain't too bright. If you place the holes facing up, the only water that's going to find its way into the pipe is that which percolates down directly above the holes, which isn't going to be much. I agree with whoever said above that, if the holes are facing up, it'll build up until it (over)flows into the holes. That's not what you're trying to achieve. Either use pipe with holes all the way around, or face the holes down.
Digger's explanation is the proper way to install perforated pipe for any purpose.
I may have misunderstood what you were saying in reference to the holes being "faced down". If the holes are 1/4 up the pipe then the bottom of the pipe is solid and will allow a trough for the water to flow in - that is what I was saying. But I disagree a perimeter drain doesn't/shouldn't collect water from the surface, that is why you should be installing a drain board on the exterior of the foundation walls. I have used many types but the best seems to be the corrugated plastic, like the type they use for real estate signs only thicker and stronger. This drain board is designed to collect any water at the face of the foundation wall and direct it down to the perimeter drain and yes this also includes surface water. All the gutters should be piped seperately as well as adequate slope away from the structure. I have built around 300+ houses, townhomes and commercial building as well as developed 200+ lots in my short career and some of them had engineers and architects inspecting. I have had a few water issues in the basements and 99% of them were attributed to cracks in the concrete walls at the top 5ft-10ft of the concrete wall. These were fixed with epoxy grout from the inside and concrete sealer. The gutters were all piped into a site built drainage system - on the surface seperately from the perimeter drain, with integrated yard inlets and proper slope away from the buildings. About 2 years ago we built a Keystone Block wall that was 200ft long and 15ft tall at its highest point. The engineer spec'd perforated 10" SDR35 with holes on one side. Since the first 4 courses were below grade the engineer spec'd the holes to be turned up with the solid side down, on top of the compacted fines (8910 stone) footing. The pipe was then covered with 2ft of #57 stone and filter fabric. We also installed a "chimney drain" at the face of the cut slope with #57 stone, filter fabric and 4" solid PVC running through the face of the wall to drain at the finished lower grade. This was all inspected by the Geotech and Structural Engineer. I agree 100%. The pipe is actually there to hold a void in your gravel. Like I said before I have seen more water running through the gravel than the pipe at the end of the drains. In reality the gravel is going to carry the waterr regardless of the position of the holes. If you face the holes down the water that collects in the pipe on the high side will run down to the closet set of holes and back out into the gravel. If you place the holes up then the water level does have to build up to flow into the pipe but the water that does flow into the pipe does not have any holes on the bottom to run out of - it makes it to daylight or the sump pump. Either way the real medium of channeling the water away is the gravel. Water does take the path of least resistance which is the gravel.
A: B: Do you suppose that "A" might explain "B"? The only reason I'm trying to convince you that the holes go toward the bottom is that, the way you're doing it, the gravel bed has to be saturated up to the top of the pipe before the pipe does any good. Your pipe is mostly a waste of time and money. Why bother?:beatsme
If the holes are on the bottom your gravel will also be saturated - hence the holes on the bottom for the water to run right back into the gravel. Actually the holes cover 180 degrees of the pipe or at the least the type we use. The water only has to travel 1/2 way up the pipe to flow in. Then there are no holes on the bottom of the pipe for the water to just return into the gravel beneath it. In reality you are only talking about a 1.5-2" difference. Your drain should be at least 10" beneath the bottom floor elevation. A solid bottom pipe will carry the water away - instead of just letting it run right back into the gravel further down the line. How do you expect the water to travel down a pipe that has holes in the bottom? It's kinda like trying to carry water in a five gallon bucket with holes drilled in the bottom. You can either distribute a small area of ground water evenly around the foundation with the holes facing down or channel the water away with the holes facing up. If your draining to daylight with the holes on the bottom, wouldn't even the slightest amount of water that was collected by the pipe run out of the holes in the bottom and into the gravel?:beatsme Either with the holes up or down the bottom layer of gravel under the pipe is the one that carries most of the water. Since water will take the path of least resistance then "B" is not the result of "A".
I have put many drains in over the past 28 years in the business. Yes the stone under pipe does most of the work but as digger mentioned your trying to get rid of the water that the stone or gravel isn't handling. by putting holes up your creating more of a bathtub of water around your footings. I understand that you have plenty of room under slab for water before it reaches floor height , but less water under or around any structure is better than more in my book.
Exactly. I'm not the least bit worried about the water staying in the pipe. The pipe is only there to provide one great big open space for water to travel, when there's more water than can comfortably travel therough all those little spaces between the gravel. It seeps into the pipe, and if it wants to, it seeps back out. When there's lots of water, I think it's counterproductive to "store" water in the gravel until there's enough of it to overflow into the holes. Ok. That's a new one on me. So, you're saying that your pipe has holes at 9 o'clock, and 3 o'clock? What I'm used to seeing, and doing, is laying pipe with holes at 4 o'clock, and 8 o'clock. What I assumed you were doing was laying that pipe with those holes at 2 o'clock and 10 o'clock. If the holes are at 4 and 8, as I described, that much water will stay in the pipe. But as I said, I'm not really concerend about that. Well, if I were trying to carry it across my living room, that would be a bad thing. But it's more like carrying it across the bottom of my swimming pool--there's already water there, so whether it leaks into the bucket or out of it, I won't notice. B is the result of A because most of the water never finds its way into your pipe--it stays in the gravel, and that's not really a problem.
Wow, this turned into a good thread! Ok, now that we covered the pipe, and by the way I just buy the pipe with holes around the complete diameter so that solved that, lets talk about fabric. I installed filter fabric over my #2 stone before I backfilled. The flexible pipe comes with a filter sock but the rigid does not. I rolled a 36" roll or fabric over the stone and not the pipe. The coiled pipe has the sock on it from the factory so the stone would go on top of the fabric. If the fabric is supposed to keep the pipe from silting in than does it not make sense to keep the stone from silting in also? That’s my thinking so the fabric on top of the stone (not pipe) and under backfill dirt. What do you guys think? This the way I have done septic pipe anyways.
I like to put fabric down first then stone and pipe more stone to cover pipe about a foot over pipe then fabric over top. You definately don't want the stone silting in.
Digger - I think we are both saying the same things just in different ways. The pipe I have always used has holes 1/2 way around or 180 degrees of the pipe - which would put the lowest of the holes at 3 and 9 o'clock positions. There is a slight difference between 4 and 8 o'clock but I really don't think that matters that much. The end result is getting the water away from the foundation. I assumed you guys were talking about the same type pipe with 180 degrees of holes and putting that side towards the bottom which did not make any sense to me. That is what I was trying to explain. This illustration explains what I was trying to say if you use this type of pipe with the holes down. http://www.ads-pipe.com/en/product_static/leechsystemwork.html Although the illustration has holes at 4 and 8 o'clock, if you turned the half of the pipe with holes down it would only expedite this situation. Jmac I am not a big fan of the pipe with sock on it - some folks think you don't need the fabric over the gravel which is a bad idea. I agree with you - I think you still need to cover the gravel to keep the fines out. The integrity of the gravel is most important.
Dumptrucker, fabric under sounds even better. I don't want to give the customers too much for the money. The specs on the last septic I did was fabric over stone and not under. This job we put the fabric in for free. :beatsme customer didn't ask for it and I didn't quote the job with it in the price but job is working out to be a very nice one so what the hell give the customer a little extra. I also thru in a clean out on the day light line for free. After the last two jobs before this guy, he's a pleasure to work for, the last two were not so nice. Goes to prove, be nice to me and I will go out of my way. That’s the way it is for me anyways. I am sure some guys take kindness for weakness just like some customers do.
CM1995, the pipe with sock has it's place but I am starting to only use rigid pipe for everything.
Last week I used the pipe with slits all the way around it. Which side was supposed to go toward the top? And if the holes don't go to the bottom, why is the top (opposite side of the holes) marked with a white line? rofessor Seriously, if we are agreeing that the pipe is really there to hold a free flowing void in the gravel, then it would be reasonable to want the water to access into that void at the lowest possible point. In this case that would be into the holes along the bottom of the pipe which is resting on the footer alongside the wall with the gravel covering it, correct? I would think that this would have the least hydraulic pressure against the wall. Ahh, heck with it. Let's just switch to AkwaDrain
Actually, what we've been doing for more than a few years now, is putting the pipe in next to the footer formwork, even before we pour. We backfill the outside of the forms with gravel, and that way we know that whatever happens, there will be pipe and gravel in place, and it will be below floor level. Of course, we add more gravel and the fabric right before we backfill, but having the pipe in place saves lots of headaches. An interesting sidenote to the fabric discussion--Just this past week, I did a foundation in a township I hadn't worked in for a while. I was surprised to learn that there, the building inspector wants to see fabric in place, at the bottom of the gravel, before he'll allow you to pour the footer.
Thats it! I get the drain pipe holes stuff but somebody Pleeease draw me a picture of exactly what the hell you guys are talking about :beatsme (I know I know..bumb Aussies )
I knew before this discussion was over I was going to have to steal the kids' crayons...
Ok... This illustrates the basement wall, floor, gravel bed beneath the floor, gravel and pipe outside the wall, and the unexcavated earth that the whole house is sitting in. The extra black line on the outside of the wall represents the waterproofing. Once the foundation has been dug, the next step is to form and pour the concrete footer. (Yes, here in Pittsburgh we call it a "footer". Other places they call it a "footing".) It helps to put some material on either side of the formwork, to hold it in place. We used to use dirt on both sides, but then we figured out that it was worth the trouble of using gravel on the outside, as mentioned previously. What OrchardEX said was that he puts the pipe on top of the footer, right next to the wall. That's fine, since the pipe still catches the water before it can seep in above the floor, but we like having the pipe lower.
First you call me a "Ditch Digger" and now you insinuate that I can only read crayon drawings ..I'll have you know that we are quite advanced Down ere.......we often use charcoal for drawing...but mostly its a green stick and level piece of dirt. (here's the serious bit) Isn't the above discussion a bit cross wired???. I mean aren't one lot talking about draining below ground walls and the other discussion is about septic systems...one trying to take water outs the ground and the other is trying to put it in Or am I missing somthin??.
Ok, thanks, that what I thought, same way as we drain a retaining wall...cepting I'll make it up into one big sausage fully wrapped in fabric. Sometimes I get the drain pipe already in the sock but whatever is available (with/without sock). The drain pipe is called "Ag" pipe down ere.
And as long as I'm drawing pictures, here are some to illustrate why I disagree with what CM is saying. In picture A, conditions are relatively dry. All the water stays in the gravel bed. In picture B, conditions are relatively wet. Water builds up in the gravel bed to the point that it begins to flow into, and through, the pipe. Installing the pipe in this fashion allows the full flow capacity of the pipe to be available at all times. In very wet conditions, obviously the water level will rise. Picture C represents the way CM likes to install his. My problem with this is that, as I said, the water needs to build up in the gravel bed to the point where it overflows into the pipe. None of the flow capacity of the pipe comes into play until that time. That means there will be more water ponding around the structure for longer periods of time. The potential for problems is increased. Obviously, it's been working ok for CM, and the fact that the pipe as he's installing it has the holes between 9 and 3 o'clock so that makes the buildup a little less. I'm sure we can agree to disagree, and everybody will stay happy.
Yes, it is. The link CM posted was of the way a septic system works, and he said right up front that he puts the holes down when doing that. There's no arguement from me on that aspect of the discussion. If it needs to be clarified, I'm only addressing taking water out of the ground, not putting water into the ground. Are we feeling a bit persecuted today? (Maybe we should declare today as "Squizzy needs a hug" day?) I was inferring that I'm only capable of creating crayon drawings. (Although I think I did quite well... ) On edit--They don't let me have anything sharp here....
We pour footers straight into the trench with no forms here. That's why I said the above. I agree if you form up your footers put the pipe in the lowest point available. For us the lowest point is on top of the footer. Nice drawings BTW, (and everybody said you only took art class for the naked lady pictures....)
So would a house sitting on a slab have this same drain system........probably not huh, since a slab doesn't have footers or is it footings......or does a slab have footers/footings? I must say I never knew about them things cause I've never done stuff like that. Yall got my respect to be able to keep track of that complicated stuff, although I do understand it now (the last drawings helped a little bit :wink2 ). So Digger, can you only draw footer drains or can you draw other stuff like giraffes and elephants......can you make balloon animals?
We don't have slabs up here, foundations are required below the frost line. In my area that's 42".
Really? I think down here its builder preference as to whether its a slab or foundation. :beatsme Do yall have to have foundations because the frost would damage the slab?
Yes, frost is the reason we have foundations. On a slab, the edges would heave with the frost and the center would not, at least not unless we had an extremely cold winter and the building was left unheated. The slab would crack and the lumber would becomes stressed, over time probably collapse. The footings are set below the frost line so they remain on unfrozen ground year 'round. You'd be amazed at how much frost heave can be, I've seen 8" movement in moist soil. Expanding water in the form of ice has tremendous power too for breaking things.
Here the frost line for footers is considered to be 36", and water lines generally need 40"-48" of cover. I've done close to 200 townhouses around here that had no basements. The ground floor was on grade, although it wasn't technically what you'd call "slab on grade', because they all had at least 24" of concrete block foundation sitting on a 12" footer. Those we did as Orchard described, and poured the concrete right in the trench. None of them have any sort of drains around the foundation. (Although, now as I think of it, a handful of them were abouut halfway buried in the front--there they had drains with the footers as I pictured, while the back was trenched as described above.) Even a detached garage around here would have that much block buried, because otherwise the frost would lift it. Uhh...I draw flies. :yup
Since we don't deal with frost too much down here, I would of never thought yall would be so restricted on foundation work. :beatsme Well I have definately learned some stuff today.
Sorry Digger - but drawing C does not show what I am talking about. I guess I will have to get my crayons out and we'll have to have an art show. Any way it will be a few days before I get back to my scanner - beach holiday and all. CB - down in our neck of the woods the frost line is usually 12" - like it ever freezes that much. Alot of our foundations are slab on grade. It's usually 18" of combined slab edge and footing. 12" to reach below the frost line and 6" of seperation between the dirt and the wood or finished floor for preventing termites and adequate drainage away from the structure. Happy 4th!!:usa
We are allowed to do what is called an "Alaskan" slab. My own personal house is built on a slab. We get to 40 below zero here at times. My house has never heaved. The reason for that is because of the two and a half feet of crushed stone under the slab with drainage pipes. There is no moisture to be trapped thus nothing to freeze and heave. The stone has air pockets in it so it acts as an insulating barrier. The slab has wire and fiber in concrete. The edges are dug down 16 inches deep by 16 inches wide to carry the weight of load bering walls.
Well, plan on drawing a giraffe for CB then. That way we'll all have something to look forward to. :thumbsup
There's a company here called "Superior Walls" that makes pre-cast concrete foundations. They are concrete walls that bolt together to form the foundations, then are sealed with some type of joint compound. The concrete panels are set by crane on a 2' bed of 3/8" stone, no concrete footings. I've yet to meet anyone living in a home with this system who likes it. The walls tend to crack and settle unevenly.
I had a customer who was his own GC. He figured it out that a superior wall system was cheaper than a poured foundation. what a pain in the ..s! We were on the side of this mountain, the trucks with the panels all had to be pulled up with the pc-300. So just unloading the trucks took 3 days. Then they set the panel's with the phrase "close-enough" being the technical term of the day. Once panel's were set had to backfill 2 feet up the wall, wait until they got the deck on the house, backfill another 1 foot up the wall and do the infill for the basement floor, wait another two weeks until they had the whole house built , then we could finish backfilling. It ended up costing the customer almost 12,000 more than a poored foundation. And the finish product is ugly. Couldn't pay me enough to do one of those again.
We work for a builder that used to use them. All in all, I've done about 100 of them. Never had a problem with any of them. We only put down 8" of pea gravel. I believe that 2' is too much.
No problem I've probablyput in the foundation for about fifteen or twenty duplex housing units that used Superior Walls. We put 2b limestone down 12" wide and 8" thick for the walls, then 2" of 1b on top of that. You had to be right on with the limestone grade, but the wall erectors would touch it up before they put them up. They were meticulous with placement and spacing, and did seal all the joints before they pulled the sections tight. We backfilled inside and out to floor subgrade, then waited for the modular units to be erected before we did anymore backfill. The only problem we had was when the builder has us backfill inside the garage unit with dirt instead of gravel. That wall pushed and had to be dug back out and straightened before it was backfilled correctly with 2b. Although it was a pain in the backside to do the work, I don't know of any other complaints or problems with this method here in western Pennsylvania. Happy 4th of July to all, and please remember just what the 4th of July is all about. :usa
subject A Cat 320 with a hammer should have been there,job would have been taken care of. Blasting is not cheap anywhere and permit costs alone will prohibit it.Also,when firing a shot,if any equipment is close by be sure and shut it down.Otherwise you will bust the cranks from the concussion.My boss had to replace 5 a few years ago and that wasnt cheap.Running Cat equipment and shooting dynamite at the same time dont mix.:drinkup
First,have to agree with those that are down with Superior Walls.There is nothing close that resembles the word superior.They are absolute GARBAGE.They give excellent job security to tapers and painters because of all the cracks that will develop in the house.I have not had 1 customer who was totally happy with theirs--complete gimmickery.Now,for placement of perforated pipe--whether you're installing a collection type system such as in a footing or curtain drain or doing a leaching type system, such as leach fields for septic,or a possible mixture of the 2,writing on the pipe goes straight up,holes are down and even.This is not a preference--it's just a recognized practice that can be clearly seen in any and all building code manuals.When some builder tries telling me different,I will leave his site,because of course he will cut corners on something else,not use enough stone---the client will remember who was the excavator running the iron when problems arise.As for the need for footing drains,any and all excavated{below grade}foundations should have them to relieve hydraulic side pressure and to route water away.