Not really sure where this thread should be, so I placed it here, but if it needs to be moved, please do so. I've been having some real trouble deciding how I want to go about compacting fill behind basement walls, footings, and general compaction. As some of you know, we've recently jumped in to excavation side of things and there's a few minor details that I just don't have sufficient experience with, especially compaction. When backfilling inside footings for a concrete floor with gravel, could we get away with using our 303CR with a hoepac? Would it have sufficient force to pass a compaction test? Or would it be better to buy a dual roller walkbehind compactor? This poses a bit of a question as well because after the footings are poured, how can you get a roller compactor over the footings without damaging them? I know if you wait long enough you can walk the mini right over if you toss a little dirt on each side. Or maybe a jumping jack is what we need? I'm completely clueless on copaction guys, if you don't know our story, we got into the excavation deal about 2 months ago and we're partnered up with a local guy in town. Needless to say, I don't want to waste their time having to explain every detail to me, so if and when, and I know it's going to happen, I have about 3-4 foundations to dig in the next 2 months, I need to go into the job with somewhat of a gameplan on the compaction side of things. To wrap all of this up, what would we be best off with? A hoepac for either excavator, a walkbehind compactor, or a jumping jack? Maybe we need a combination of a couple pieces, that's just fine as well. Cost is not an issue, we will buy what we need to get the job done right, I'm just curious as to what everyone else uses and what performs well on a wide variety of applictions moderately well. Thanks!
A jumping jack will do the job, but will take a bit of time. A walk-behind plate compactor is the way to go. What will you be filling the footers with ?? We fill them with crushed stone. Also, I have never seen anybody compact stone inside of a 8" footing. I would never compact it unless it was more than 2ft thick. We only compact around the frost footer. If it is a big footer and going to take alot of material, then we will fill with mine rock which is shale on top of coal and then top it with 4" of crushed stone As far as walking the machines on the footers, we put the stone in with a dozer and have never had a footer crack yet. I have even walked 42,000lb excavators over top footers with no problems.
We use a jumping jack for the big lifts then use a smaller plate after final grading for concrete, usually at least. If you have the money i would buy a big plate compactor and a jumping jack for tight areas. We also have a hoe pac that we use for backfilling our sewer/storm/water/utility/etc trenches but the backhoe usually isnt at our house sites.
Most of the time, plans just call for undisturbed soil or compacted soil as the base for the footings. It sounds really strange, especially when you say you throw 4" material under some. I've looked at 3 sets of house plans and all of them clearly say 16x8" footings on top of undisturbed or compacted soil. I'm sure I'm going to feel weird when I go to dig some footings and have the plans not call for any gravel, but I guess you gotta follow the plans. I'm still unsure why you don't compact gravel inside the footings for a concrete floor? Wouldn't that need to be compacted? 2 sets of plans I've looked at so far called for 4" of compacted sand/gravel mix for the basement floor. I guess different places call for different practices. Sounds like we need a big plate and a jumping jack for small spots, kinda what I figured I'd need. The jumping jacks aren't too expensive, but what would one expect to pay for a big plate compactor, something in the 1500 pound class? Do we need something that big?
Usually the forming contractor or the general contractor of the site deals with the compaction of the backfill so its his azz when they put too much pressure on the green wall and it cracks. Its the way the excavation contractors do it here they don't have anything to do with the compacting they are there to-do the digging and excavating. The building contractor is also responsible for the drainage around the foundation all the excavation contractor does is move the drain rock and place it where the building contractor wants it. The only time you would do compaction is if you are doing utility work or building road. I would rent what ever you need for compaction jobs you may want a small plate compactor they are cheap. For the bigger jobs you rent a bigger plate compactor some of the contractors rent 1000lb diesel powered units. I think you really should let the building contractors deal with the compacting when it comes to basements and foundations. You will need a good laser level they are a must. The contractor I worked with has one its not cheap I think it costs 2500 dollars or more. We used the censor on a grade stick it had the adaptors for mounting the sensor on the machine but it was a waste of time. Getting out of the machine and checking the grade was much easier. If you get a foundation or basement dug and its close to perfect grade they would give you their left ***. It saves them time hand digging and raking. Back to the compaction thing you have to remember you get the basement hole dug there will be cases where you won't get the 312 into so having a hoe pack on it won't work. The 305 will fit but won't have the reach so your end up using a hand operated compactor (plate or Jumper). If you end up doing alot of utility work like water lines etc a hoe pack will be worth it. Say you got on a job like a large subdivision where you are digging the trenches for the poo and water pipes a hoe pack will pay for itself.
I think if we get enough utility work, we'll buy a hoepac. Our dealer will rent one to us to let us figure out what size we want, and then we'll buy one. I don't know if I can get away with not compacting footings, but maybe it's something I'm over-thinking. I guess I'll find out when we get our first job in which case I'll rent something first to see what works best. We just got our laser system a couple days ago. I haven't had a chance to check it out yet, but I have been told it's already setup to mount the reciever on the excavator stick, so I need to figure out if they sent us a bracket to mount to the stick.
compaction,compaction,compaction. I found that most footings are dug to exact depth and footing is poured on undisturbed earth. Masons will form on bottom of trench no stone needed and no compaction needed but trench has to be wide enough and should be clean and smoothed with bucket as you go check grade every 4 feet or so using laser and stick man. Don't forget dewatering trench with trash pump this will be needed if it rains or you hit water table. The laser on the stick is awesome invention. The reciever mounts magnectly to stick. I wish I had one just make sure you do not change the configuration of stick as you go because this will change grade. The back fill is another story. That has to be compacted in lifts and this is the most sensitive area of any new foundation. If I had my way I would do all of this in 12" lifts and a plate tamper on my mini excavator. If the walls are block and not poured you have to be very careful not to nock block loose. If this is the case definitely use a jumping jack for the first lifts and then walk behind plate tamper for last two lifts. The slab on large jobs with no basement would be rolled with double drum roller. We have a 70" 18000 lb unit for this. Residential jobs use walk behind plate tamper and the biggest machine you can get into the basement. This work seams to always be in my contracts and is tested by an independent company, paid for by owner or general contractor. Most specs are 95% compaction some are 98%. The independent testing company will tell you about bad areas and these have to be either compacted better or dug up and redone with sand gravel mix material called bank run. This would be a change order for me if the material is compacted with best practice and material is not suitable for the 95% rating. Poured walls you can drive a mini over them and can use a plate tamper on your mini, best way and fastest. We are doing a large site job today 160 x 60 building and we installed bank run for the pad up to the areas that we would dig footings, and compacted before digging footings so we would have access to pad area for dump trucks to dump 20 trucks of bank run and then this would be topped with sand or crusher run for finish grade and compacted again. We also had to rough grade entire site down two feet below finish grade and rolled (compacted) this material (clay, rock) to a 95% compaction. This is called proof rolling. Compaction sounds easy but is and can be complicated and the failures come from not doing this correct. The independent testing company is your friend not enemy as some guys think because they protect you from law suits down the road when concrete slab fails. My education has come from the collage of hard knocks and I wish I had the right equipment from the start. If I could not do this work I would not have any site work at, all of the excavating contractors do this as part of the service they offer in my area. One thing I know for sure is you never compact to much ( unless using a double drum roller, save that for another post).
Thanks for all the info! Sounds like I was on the right track, sounds like most of your plans end up like the ones I've looked at. Footings on undisturbed soil, backfill basement walls and compact in 12" lifts, and compact sand/gravel for concrete floor/slab, sounds really familiar. Sounds like I need a jumping jack and maybe a hoepac.
A Jumpin Jack will do most of what you describe, up to 20-24" lifts, manoeuverable and cheap to hire/buy. You need a 1600lb plate compactor to acheive the same compaction, and the platey will bring the trench down on you almost every time. We have our own penetrometer so we can test at the start and test again after some compacting. This way we know wether we are acheiving something or wasting time. We always have an independent engineer come out and witness our final compaction tests.
How much does a penetrometer cost? And where can I get one? Or should I even bother? Sounds like the jumping jack is the way to go. How did you like the Dynapac Squizzy?
go with the hoepac, we have the stanley equivalent of a hoepac on our 690E deere excavator, we'll outcompact and do a better job than 10 guys on jumping jacks. on commercial buildings, we start at a corner, compact both sides, fill up so we can track over it, straddle the wall, and compact both sides as we go so we don't tweek the wall. works wonderful, cement guys love it because they can get onto their floor work couple of days faster than if they or we used jumping jacks remember the most important thing about soil compaction. to make it MUCH easier for you, find out what the optimum moisture of the soil should be, and try to keep it within 2% either way. proper moisture content in soil acts like a lubricant for the soil particles to go together MUCH easier. you asked about a pentrometer. i wouldn't own one, i want a soils professional telling me whether i have the density or not and him documenting it. that way the monkey's off my back in case something isn't right
I 2nd dayexco soil pro all the way and GC pays for it not me. after reading my post I did write "double drum roller" sorry single drum roller is what we have. As for soil moisture content what do you use for testing that. What does it cost. An off topic questions is what would it cost to add third valve on a excavator and have any of you done this. I would like to add this to my 17k excavator so I could use it for tamping.
Like I meantioned I bet most of the house sites Scag will be working on will be too tight to get the 312 around the excavated basement. You don't want to sink yourself into debt buying attachments for the excavator when you can get hand tools cheaper. It is very very rare for a local excavation contractor to do compacting with a hoe pack. Its all done with jumping jacks or big plate compactors if you got large areas when a viberatory roller like a Ingersol Rand. Out of the 10 excavation contractors in my community only one contractor has a hoe pack for a rubber tired backhoe and it sits 99% of the time in the yard rarely gets used. Some of these contractors have been in business for 30 years. Rent what ever you need because compacting shouldn't be part of your services unless you want to put your azz on the line because the house foundation settled because you didn't compact enough. Everybody wants to put the blame on somebody else when something screws up. The building contractor is supposed to be incharge of everything that goes on with the site. They are responsible for the foundation of the house they have the building permit in their name. They deal with the engineer they have their john henry on the engineers papers. You want the reputation for doing fast and accurate basement and foundation excavations. Once you have that people will keep hiring you to do them. Building contractors don't want to hire somebody that is slow and inaccurate.
That's strange, I'd say 8-10 guys out here have hoepacs. Just looking around seeing what everyone else is using makes me think about what I should be using as well.
i'd like to make one point very clear, unless you're a civil PE....i would never, EVER assume the responsibility on any compaction job of whether or not the job is done good enough or not. typically, contractors don't have the expertise, nor the equipment to make that determination. that being said, we make good money in compaction. many GC's hire us simply for the reason that we can backfill foundations so much faster, efficiently than they can with laborer's/jumping jacks. they'll provide a soils tech to oversee, sign off on our work. like i said, a hoepac on an excavator outworks a min. of 10 men with jumping jacks, does a better job. the GC's like this because they get their jobs done faster
I had the same thoughts that even though you're doing the compaction, you still aren't 100% liable for mistakes, much like building an engineered wall. If I was to build a wall spec'd by an engineer, have someone watch me build the wall, and then 5 years later the wall falls over, how is that my fault? That would be an engineering fault. Am I correct that this rule applies to compaction as well?
For us every house foundation has to be engineered stamped before any construction begins even if the house is sitting on solid rock. As for backfilling its done with a machine and hand operated tampers. You have to be really carefull about backfilling because the walls are still green. Its nothing but formed concrete for foundations and footings concrete cinder block isn't used. The building contractors let the walls sit for a day strip the forms off and start building. If you get too much pressure on the wall from backfilling you can easily crack a foundation yes a 10" thick concrete wall can crack when the concrete is still green. A building contractor doesn't want any kind of heavy viberation near the foundation all it would take would be a slight bump with the excavator and cause damage. The backfill is done in small lifts so the jumping jacks and plate compactors can compact the material. Backfilling is usually done after the contractors get the water proofing on and the drainage in and the first deck ontop of the concrete foundation. Some of backfills take 20-30 yards of material or more and the foundation takes up a 3000 square foot foot print. It usually takes 20 yards of inch and a half stone drain rock then material is trucked in for the backfill the most common is pit run from a gravel pit. I guess you guys in the US do more compacting on jobsites for us its not worth our time the homeowner won't pay a machine with a hoe pac to do a job that a jumping jack or plate compactor can do. Like I meantioned the one contractor in the area is the only one with a hoe pack it got used on one job for 1 hour in the whole year and I was the one using it.
I understand where dayexco is coming from, but with scag only doing residential home sites a jumping jack/plate combo should work out just fine. If you start doing a lot of commercial jobs, and site development then a hoe pac would be an essential tool.
Another thing Scag's dads wallet is already getting pretty thin with all the new toys they are buying for the new venture :bouncegri They are going to have to save up the money so they can buy themselves a 2007 Kenworth T-800 dump truck and a brandnew tilt trailer to move the 312 around. Seeing as they want to get out of the landscaping bus they are going to need to buy a 20 ton excavator next :yup
We use the penetrometer to help us do our work quickly and efficiently to a high standard. If you don't have a clue how your compaction is coming along...you just guess...and possibly waste time compacting when you may not have to. I have a penetrometer so I know when I'm done and when to call the engineer for the compaction test. I also am able to pick up areas which are much softer before we start, saving me further time by knowing where to operate. I don't certify my compaction...an engineer comes out and tests it, but I thought thats what I said before. Penetrometers are a good guide but not the most accurate. They have to be calibrated (weighted) and certified for your area/soil types. Its best to ask your local Geo engineers what is the best tool to use to give you a good guide. It really saves a lot of time being able to check yourself. The Dynapac is going great. We had to dig out 9' for a 220 ft long retaining wall. The plate compactor kept bringing the back slope down on us so we did the lot with the Dynapac. 2 passes hit the mark on most of it and we got compaction down to 30".
i do have a clue as to the progress of our compaction efforts, because i insist the property owner have a soils tech onsite at any time we are there to document the progress. i refuse to assume that liability.
In over 40 yrs in the business and we never once had to have a compaction test on a residential site.
that's your call rino, i guess i refuse to assume the liability of having driveways, landscaping, sidewalks, etc etc settle because of improper compaction. i might "think" i'm doing an adaquate job when in reality it might be light. i don't absorb that expense whatsoever. i tell the homeowner to hire the soil tech of his choosing. should they refuse to hire one, i make them sign a waiver saying as much and relieving me of any liability in case something happens down the road.
you all make some great points! Why does this topic never come up ? I think that this is more important than any digging, grading, etc. This is the most important thing we do as excavating contractors. How well we do this could be the diffence between a good job or a new floor, footing, parking lot etc. This is what can seperate you from the rest. In my phone book about 200 contractors. Not very fun work but can and will make you money. I wish I had a hoepac but do all with jumping jack, plate tamper, and single drum roller. I like the idea of testing myself before soil pro test. You can over compact with a single drum roller and just waste time and money. Knowing when to get off the area is the trick and that is hard to tell. Moisture content I read somewhere and have no idea how to check that HELP. Keep this topic going because I think most residential and smaller guy's don't compact and the cost of doing this is not that much along with some know how.
think about this. if you want to hire a flock of sheep to pack your lifts.....or use a jumping jack, a walk behind vibratory plate...OR a hoepack...have at it, make money at it...but why in God's green earth would you ever assume the liability of whether or not you've compacted that soil well enough or not? geeus...put it on the shoulders of a professional. if a driveway settles, a building settles, landscaping settles...why in the world would you want to assume that responsibility? trust me, it's far cheaper for you to have some soils tech to tell you that your test bombed, and you have to make a couple of more passes on it...than to pay to tear out/replace a structure/pavement because it wasn't done properly. we're the pro's at digging it up, putting it back...and we all know we're good, but why don't we have somebody signing off on the deal saying we're good enough?
Dayexco, I think you misunderstood my point. Not saying to accept that responsibility no way. Agree with you 100%. Checking before soil pro checks your work not a bad idea. Save time and money in the process. Still have to be tested by soil tech of course! I never accept responsibilty for any compaction and don't intend to ever. I don't move onto the next step untill soil pro gives approval. I insist on site work that it be done this way. Residential different story. Have not run into failure yet but it could happen. Talking about a driveway and basement floor at a new house. Not a parking lot or 50 sq ft of concrete. I would feel better if tested by soil pro for driveway or basement floor but have not ever seen it done. Same rule for me, I do not accept responsibilty for it but want to get paid to do the work for sure. I have a neighbor that has a new 250k home and his driveway has a big area in middle that settled 12". Sub contractor that did the work buired trees from the site under driveway. Hello! The Home Builder was the one who paid to have it fixed. Not fair, but it would have been smart for that guy to have driveway tested! To sum it up what I am saying is give me the work I want it, but have it tested by soil pro and I should not and will not pay (unless I quote the job that way) for it because I don't accept responsibilty.
We really only test if the city requires, such as commercial jobs, and under roads. Half the time they just watch a loaded dump truck drive around and watch the ground under the tires. If it moves, no good, if it doesnt you're good. Its either that or they nuc it, and that doesnt always work out, as the sample they tested could be different from the material in the trench, even though it was from the same pile/pit. Having someone come test your compaction on a simple house site seems a bit overkill, I bet there isnt one contractor around here that tests for compaction on a residential site.
I have no idea how you got the impression that owning a penetrometer "assumes" responsibility for the compaction. The engineer tests it and certifys the compaction...pretty simple really. I also doubt very much wether a waiver signed by an owner would hold much weight in court. You are the professional and they are the uninformed consumer. You are responsible for doing the job to appropriate standards regardless of wether a Geo engineer is present or not. If we are going to make analogies hows about the electrician getting the owner to sign a waiver that a house doen't need an earth wire??...the elctrician is still responsible to the appropriate standard no matter what the customer tells him to do. Much better to just price the compaction test into the job and get it certified. Costs us $100.00. Thats money well spent I believe. I have been fortunate to come by a penetrometer to help us with our work...just like our laser..its a tool the helps acheive the job. And on a final note; certification or not; as the contractor who did the work, you are responsible to some degree wether you like it or not. The compaction certification does not necassarily wipe the slate totally clean.
I 2nd that squiz if basement floor in a new home drops 6" and that home owner is suing Home Builder who is suing you or me. The commercial site work at least in court you could say: hey the general had an expert test and he said it was "ok" to proceed. But in residential home with no expert to test you are the excavator, you are the expert wether you like it or not.
We have 2 engineers that are geo-techs at our disposal and ready for hire, I'm not too worried. All I need now is a basement dig and a hoepac and I'm good to go.
Ive got a basement dig starting tomorrow.:thumbsup 7' deep, the house is 50' off the ocean. its gonna be slow cause all material has to be hauled offsite, i only have room for maybe ~100 yards
jmac, you're the "expert" if you allow yourself to be. granted, 90% of the soil conditions might not warrant the homeowner hiring a soil tech. BUT, before i lay my butt on the line, stand up in court and have some attorney ask me what my credentials are in the soils field, and what quality control tests i'd taken before i thought it "good enough"...i'd tell the homeowner, to either hire himself a soils tech....or give them the name of one of my detested competitors
You should never say it good enough, your not qualified, your compaction certificate will say wether its good enough.
The current International Building Code (may not be used in you area) states in garages and basements where concrete will be place must be on undisturbed soil, less than 24" of clean stone, less than 8" of uncompacted soil(i would never do), or engineered fill. On garages I now use clean stone as deep as needed without any compaction, I have an engineer certify this. I have trouble compacting around foundations, the jumping jack tamp doesn't do well on more than about 6" lift, it is hard to manuver over uncompacted soil. It takes forever to backfil. On the other hand they are worth having for hard to reach areas. It would be nice to have a pentrometer and use it as a check as we are compacting. In our case a soil tech comes out every 2', he does not necessarly stay on small jobs all the time. I am a building contractor and do cover my tail as much as possible. Tim