Building a basement

[bluefish]

Ok, we're looking at starting to build our house this spring/summer and we want a basement. We don't know anything at all about basements and concrete work. I'm looking for ideas and advice or anything as to where to start with just learning about it. Even if we hire it done (likely) I'd still like to know enough to ask intelligent questions and be able to hopefully pick out a decent contractor. Thanks!

[highlands]

Make sure they use plenty of steel (rebar) of sufficient size (strength / diameter), tap it down (vibrate), sufficiently strong concrete (psi / low water) and have good packed drainage around the walls as well as on fresh earth, not fill. All key issues. If you don't understand these thing get someone who does who is _NOT_ the concrete people / builder. You are talking abut the foundation of your house. Everything else sits there. Get it right.

Cheers

-Walter
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont
Read about our on-farm butcher shop project:
http://SugarMtnFarm.com/butchershop
http://SugarMtnFarm.com/csa

[ronbre]

most important is site prep..very level and very well compacted..footings should be dug around the outside deeper than the floor..lots of rebar or reinf wire should be added to the concrete mix and if you are putting a drain in ..put it in before pouring..if you are putting drainage tiles around the basement have them put in as well as any thing that has to be put into the floor first...they should be using a transit and leve everything..plumb and square..when walls are built some should be reiniforced with rebar and with concrete filling some of the blocks and all headers should be put in where windows and doors will be going..

if reiforcing piers are put in..they should be dug deep with footings where piers will be.

[geo in mi]

Best way to start might be to rent an auger with attachable extensions to test dig in several places where you intend to put it, before you commit to a contractor. It will be just like a regular auger-type post hole digger, but with screw on extensions that will let you go lower (yep, pretty labor-intensive, but worth it) You will then have a pretty good idea of what's under there, such as rocks, possible debris(if something was built there before) soil conditions, sand, shale, clay, waterlogged conditions, etc.

Then you might spend the twenty or so bucks at the BB store rack for "How to Build a Basement", or some such book(Google it) to gain some know-how before you start talking to various contractors. Then you can talk to them with some degree of intelligence.

[MushCreek]

In most areas, modern building codes require extensive drainage systems and waterproofing. If you don't do this, you run the risk of being one of millions of homeowners with an 'indoor underground swimming pool'. They install perforated pipe around and under the foundation. They backfill with gravel, and cover it with landscape cloth so it doesn't become clogged with dirt over the years. The piping is either connected to a sump pump, or drained downhill of the house. It's also important that they use good waterproofing practices on the foundation walls, usually some combination of a sealer, and a drainage plane, like dimple board, which prevents water from sitting against the walls. It's also important to have the yard properly graded to conduct water away from the foundation. Generous roof overhangs and gutters also go a long way towards keeping things dry. There's (almost) no excuse these days for a damp basement, unless you have a lot of ground water to deal with. Believe it or not, even a perfectly waterproof basement will still tend to be damp in the summer! That's because the warm moisture-laden outside air hits the cool walls, and they sweat, just like a glass of iced tea. Many people find they need to run a dehumidifier in the summer.

[fishhead]

One way to keep you basement drier would be to insulate it from the cold ground.

[ErinP]

We dug ours with a bi-directional tractor and a skidsteer. (it's a daylight/walkout though, so no hole, exactly)

We've already poured the footers. We'll be dry-stacking our walls with concrete block and using surface bonding cement. A really DIY friendly method, btw.
A couple of books I'd recommend are:
Do It Yourself Housebuilding by George Nash

Independent Builder: Designing and Building a House Your Way by Sam Clark.

Earth Sheltered Houses by Rob Roy (we're not actually building an earth sheltered house, but half of the book is basically about building a comfortable, dry, properly insulated basement and he does surface bonding on his blocks)

The first two are just basic house-building books, from the ground up, for do it your selfers. Very user friendly LOTS of pictures and drawings. One is 500 pages, the other is 700.

[ErinP]

Originally Posted by MushCreek

Believe it or not, even a perfectly waterproof basement will still tend to be damp in the summer!

You don't live in a dry enough part of the country.
Our basements have always been dry.
My folks', on the other hand, in more-humid eastern Nebraska, is damp sometimes.

[fishhead]

ErinP

We've already poured the footers. We'll be dry-stacking our walls with concrete block and using surface bonding cement. A really DIY friendly method, btw. "

Does the surface bonding cement replace the usual joint cement? Does it withstand inward pressure from the earth as well as a wall made normally?

[bluefish]

Thanks all!
Erin P, we've already got the Sam Clark one. I'll definitely look at the other two. Thanks!

[ErinP]

Originally Posted by fishhead

Does the surface bonding cement replace the usual joint cement? Does it withstand inward pressure from the earth as well as a wall made normally?

Yes!!
In fact, structurally speaking, SBC blocks are stronger than jointed blocks.
Surface bonding cement is basically a mortar with fiberglass in it.
So, instead of having all of those narrow, lateral joints in a standard block wall, you've created a bond that goes over the entire front and back vertical faces of your blocks.
Fill the voids with concrete and you've got something that is stronger than a poured wall, too.

Here's a pic of a wall that has been dry stacked and surface bonded. Despite the fact that it's not used often, it has been in use for decades.

Here's a blog that talks about it, too:
n74tg's blog
Tony is also a frequent poster over at Countryplans.com which, along with the HT board, should be a forum any homestead builder has at their fingertips. Yeah, they'd like you to buy their plans, but most of us don't. The info and experience there is completely invaluable!

[fishhead]

Thanks! My only experience with it was putting it on the foam I put over exposed blocks in my foundation. It sticks surprisingly well.

Do you trowel it on or roll it?

What do you mean by filling the voids? The little ones on the surface of the blocks or the big ones in the blocks?

[ErinP]

Originally Posted by fishhead

Thanks! My only experience with it was putting it on the foam I put over exposed blocks in my foundation. It sticks surprisingly well.

Do you trowel it on or roll it?

What do you mean by filling the voids? The little ones on the surface of the blocks or the big ones in the blocks?

Yeah, the big ones on the blocks. Depending upon the engineering of your project, you probably don't need to fill every void of your blocks. But, it makes a really strong wall if you do.
And yeah, "void" refers to the main holes in the blocks. Rebar runs up through some of them from the footers, and those always get filled in.

And yep, SBC is trowled on like any other mortar-type of material. IIRC it's supposed to be 1/8" thick

[Beeman]

http://www.sakrete.com/projects/proj...lessBlockWalls

On this site they don't recommend surface bonding cement for basement walls. What type and brand are you useing?

[wy_white_wolf]

Originally Posted by Beeman

http://www.sakrete.com/projects/proj...lessBlockWalls

On this site they don't recommend surface bonding cement for basement walls. What type and brand are you useing?

That's not what I see.

•Do not build foundations, basements or retaining walls above 4 feet without engineered designs. (Check local building codes.)
Other Uses
SAKRETE® Surface Bonding Cement also has dampproofing properties so that it is effective as a water resistant coating for concrete block walls, ie., basement walls, foundations, above or below grade. When used this way, only one side of the wall may be accessible for coating. Depending on the severity of conditions, other measures may be necessary.

[ErinP]

And really, you're not supposed to use 2x4s/6s to frame your house, either, without an "engineered design."

[retire2$]

I dry stacked my 12 inch wide block. When I figured the cost of the fiberglass and the extra cement to parge the inside of the walls and the extra time involved I decided to pour each core with concrete. I built a form approximately 4 foot long to slide along the top of the block and ran 2x4's down from the form. A concrete truck drove along the wall and filled the form with concrete. I would slide the form along the wall and filled the entire wall. I used a 3000 pound mix and then had the driver add a little more water so the mix would be fluid enough to flow through the cores of the block. I also asked for pea gravel to be used in the aggravate instead of the larger stone that they normally use. I used rebar to settle the concrete. I put rebar in the block about every 6 foot. I do not have any of the rebar in the wall tied to the footer. For the floor I had the concrete company deliver pea gravel and shoot this into the basement. With the force from their shoot and my home made shoot I was able to cover the floor with 6 inches of stone. Doing this was WAY easier than trying to shovel and wheel barrow stone. After the stone was added and leveled I poured 4 inches of 3500 pound mix concrete to finish the floor. I did not put a french drain around the outside of the basement wall because I did not have anywhere to run the pipe. I do not like dry wells for outside drainage because if they fill up before they have a chance to drain the water will stay against the wall and you will get water in the basement. When I finished the basement I put styrofoam against the wall and then built a regular stud wall and added 3 and 1/2 inch insulation. Putting styrofoam on the outside wall would be a good idea if you are not going to finish the basement. Also, the price of metal studs is comparable to wood if you are going to finish your basement off with drywall. I used T-111 so wood was a better option for me. Good Luck with your house building. P.S. Take pictures along the way. I've built all three of the houses I have lived in. It sure would be nice to go back and see the work in progress again.

[kvr28]

here is our 12 inch dry stacked home using rob roys method



here is our blog on the building of it, I'm only up to the shell being completed, have to finish posting all the pics

http://kvr28.blogspot.com/

[Darren]

I agree with MushCreek's post. I'd add don't use clay for backfill against a wall. I'd use sand or small diameter gravel up to within a foot or so of the surface sandwiched in the geotextile. I'd suggest pouring a floor after the footings and embedding waterstop around the periphery so that it extends up into the walls when they are poured. That will make a permanent barrier to prevent water from penetrating the joint between the floor and walls.

The waterstop ends should be joined using the hot shovel method so it forms a continuous barrier unless you have a walkout.

[rambler]

I live in a moist Minnesota area with tight clay soils and frost that can go 5 feet deep, so build STURDY and build DRAINAGE into the system. Very very important 'here'.

Mine is poured concrete, worked well but they lacked drainage, so water will ooze up from cracks in the floor. Walls are holding well, but floor has fine cracks. 1926 house...

The last 10 years or so they do treated wood basements around here.Not sure I'm sold on that idea; easy for a person with woodworking skills to handle, but... I donno. Just mentioning the option.

Think well about drainage. It's important. Hard to fix if it isn't done right the 1st time.

--->Paul