Educational Material on Quality Foundations

[wackattack]

Although I have a partial (Biomedical) engineering background I know very little about foundations. When reading through this forum I see a lot of comments about the work in their region being "poor at best, awful at worst". I hope to be building an ICF home in the future and I was wondering if the good members of this forum have any suggestions for reading materials on foundation construction. It would be nice to know how to tell quality construction from "poor" construction.

Also, a lot of comments have been made as suggesting extreme difficulty in making concrete impermeable to water. It would be nice to know what the best sources of information out there are. As of right now I'm not sure how to cut through product promoting bias.

 

[wackattack]

Heh, I accidentally hit "post" instead of "preview". As for best sources, I am looking for quality comparisons of different technologies for keeping basements and foundations dry. Reading company websites isn't exactly the most reliable method of learning about product performance.

Thanks for your time,

-W

 

[GeoPaveTraffic]

What works best somewhat depends on the area of the country where the building is located.

However, a couple of things that I believe would apply everywehre.

Choose a contract that does a large number of basements similar to what you are having built.

Use poured in-place reinforced concrete.

Have the steel and concrete tested by a laboratory. Tell the contractor that you are going to have it tested.

Place at least one drain tile on the outside of the basement wall at the elevation of the footing. Extend free draining material from the elevation of the drain tile to with a couple of feet of the ground surface.

If you want to use the "belt AND suspenders" method, place a second drain tile under the floor slab adjacent to the footing.

Conect all drain tiles to either a sump or daylight them near by.

In my experience the drain tiles are the most important aspect of keeping below grade walls dry. There are several waterproofing products that can be applied to the outside of the walls to help. I think they all work fairly well if they are installed propoerly. Note that proper installation is not easy with some of these products; but if improperly installed, you have wasted the money.

 

[civilperson]

Keep the water away using positive drainage around the structure. Concrete is water resistant, NOT impermeable. Drain pipes around the foundation below the floor elevation will keep water pressure from the walls.

 

[csd72]

Get a good structural engineer to detail and inspect it- foundations are the one thing that is usually impossible to retrofit.

 

[DarthSoilsGuy]

A good general book is "Building Construction Illustrated 2nd edition" by Francis DK Ching.

it won't help you with the question you pose, but it is a good general book for the whole project. i imagine you'll want to know about the rest of the construction and this is a good starting point for almost anything in home construction.

get a structural or geotech engineer on-board, maybe both. A good testing firm (geopave post) will be a good starting place as they can probably do all the consultation and testing. let him/her review the probably pre-engineered wall and adjust the design to your concerns and to the site. your concerns are real, but the site will have a lot of say on this issue.

get a contractor who does a lot of icf foundations. The egr and the icf merchant may have some good recommendations. be aware that there are some framers out there who don't have foundation work, but won't tell you b/c it might lose the framing job for them. It's a tight work market right now in USA residential with the rise of interest rates and the sub-prime mortgage debacle. this can be a good and bad thing. more or less, don't be afraid to have different sub-contractors.

 

[oldestguy]

OK guys, here I go again.

By all means don't consider what you see in architectural or structural guide books as the correct way to keep your basement dry.

Think about the mechanics of the situation. Yes use sub-drain pipes, but that's just a start.

You will commonly see details that say "use gravel around the drain pipe" Many designers and contrzctors do that a lot. Fortunately most of their jobs don't carry much or any water. Gravel is not a filter. You need a filter to hold back the soil.

What I have seen happen too many times is these drains plug up and don't function after a year or so. What has happened is the gravel is not a filter for the fines. They generally are silts and very fines sands, some coarser clays which easily pass the open void spaces in gravel and, if they do not wash out with the water, they plug the system. If they wash out, you get settlement of the area from where they came. A sock on the pipe is not suitable by itself, since the crud builds up over the slots and then nothing passes.

So if you want to see the mechanics of what is best for drainage, look up the NAVAC manuals and see the formulas that truly are correct as to how to design filters to prevent this mess.

However, if you are not inclined to do that, simply make sure that any water flowing toward your system has to pass through ASTM C-33 concrete FINE (not coarse) aggregate. We call it concrete sand. It is the best all around filter you can get and with the usual slotted plastic drain pipes will function fine. A little sand enters the pipe, but soon the coarser particles will bridge the openings.

I'd like for the members of the group here to show you a college text book that tells you about filters and what the best system is for keeping sub-drains functioning, and I'll bet very few such books are out there.

This use of concrete sand as a good filter was first investigated by the Corps of Engineers back in the '30's, but few modern day references and most building codes don't know about it. On that basis you may have to argue with a building inspector. If he insists on gravel, instead dump in a full mix of sand and gravel that would be used in concrete. It also works.

As a writer above says, use plenty of drains. I space them under floors at 15 feet or less and underlay the concrete floor also with concrete sand.

Take it from this old guy (79 now) you can't go wrong by keeping the gravel off the job site and instead backfill the drains with concrete sand. I've never had a job fail with this as backfill.

 

[oldestguy]

Oldest guy is back again.

I found a text in my librry that is pretty good on this, but not perfect.

"Introductory Soil Machanics and Foundations" by Sowers and Sowers. Mine is Third Edition. They cover it quite well.

 

[roscoe]

I am getting ready to do the drainage tile and backfill for my basement wall for my hillside home (I am the Engineer and the Contractor)and was planning on using drain rock as backfill, but now I am looking into sand as Oldestguy mentions above and it really makes sense.

There are a couple of other issues that I would appreciate feedback on....

Due to the configuration of my basement wall... (it is not a straight shot)...., I have to make about 3ea 90 deg turns with the drain tile in order to reach "daylight" on each side, and want to minimize the fittings I use for the drain tile, so was thinking about using a "vertical" style pipe such as ADS Advantage 12" , or Varicore Muliflow, (they both come wrapped with filter fabric).

http://www.ads-pipe.com/pdf/en/AdvanEDGE_(L-1074).pdf

My question is, first, does anyone have positive/negative comments regarding the use of this type of vertical drain pipe as a drainage tile instead of the typical 4" round perf pipe? One possible negative that I see, is that I will not be able to install "cleanouts", which typically I would put with the 4" round pipe using Wye fittings to connect to a vertical solid drain pipe, connected to a clean-out box at grade near top of wall. Based on what I've read on the performance of the concrete sand backfill, it seems that the cleanouts might not be necessary. Does anyone have experience where they actually used one of these cleanouts to remove silting from a perf pipe? Are cleanouts an "absolute must"?

The wall is about 100' long, 10' high with a total of 6ea 90 degree corners, and two points to daylight the drainage tile. The advantage to using the 12" vertical perf drain pipe, is that it has a thinner vertical cross section and it helps me for making the bends on a semi-tight radius without having to use fittings/bends.

The location of the drainage tile is adjacent to the footing, in a trench approximately 4" deep x 6" wide. The 12" vertical drain pipe would be inserted 4" deep into the trench and so about 8" would be protruding above the footing elevation. I don't think this is a problem, since the invert of the drain pipe will be 4" below the footing. (Also the interior slab on grade is 5" thick and installed on top of the footing), so that makes it about 9" above the drainage tile invert. I hope this is clear enough to follow...

any input would be greatly appreciated.

by the way the wall will be completely waterproofed with Tremco ParaSeal Bentonite waterproofing, and a drainage board.

 

[COEngineeer]

Check out

http://www.quadlock.com

. I just used specified their product on one of my project and i thought they have very good quality product. The project I did used this system all the way to the top plate of the roof. It transition from 8" thick fdtn wall to 6". It is pretty slick. As far as water problem, I agree with civilperson. You need to slope the soil away from the house. And put perimeter drain right next to footng.

Never, but never question engineer's judgement

 

[vulcanhammer]

Since oldestguy has brought up the subject of the NAVFAC manuals, the way one accesses them on my site has changed.

NAVFAC DM 7.01/7.1 is found at

http://www.vulcanhammer.net/geotechnical/general_soil_mechanics.php

It's interesting to note that this is now a UFC (Unified Facilities Command) document 3-220-10N, but the document has not been changed.

NAVFAC DM 7.02/7.2 is found at

http://www.vulcanhammer.net/geotechnical/foundations.php

There's a new UFC document (UFC 3-220-01N) to replace this too, but personally I'm not too impressed with the result.

In each case I offer both documents.

http://www.vulcanhammer.net

http://www.vulcanhammer.info