Remodel Basement

heavyparts

I aam in the proccess of remodeling my basement into a home office and I have some questions that I need help on. The walls currently are block and have 6 in of insultation that is lagged into the block and has a puffy apearance to it should I remove this and attach the walls to the block and use the styrofoam panels betwen the studs or should I leave the insultion on and build the walls out from there and attach the walls to the floor and upstairs subfloor. If a use the 1st one what would you recommed for the side walls 2x4 of 2x2 and if I use 2x2 how would I install the electrical Boxs. On the floor I would like to add a sub floor should i use 2x4 laying them flat so Im only loosing 2 in of ceiling height any other help you would have please let me know thanks Mark

Mike Finley

As long as you don't mind losing the square footage, I'd reframe the new walls (2x4) in front of the insulation. This is very fast to do and the only real problems are losing square footage and creating deep windows if you have them. You also get the advantage of nice quick true square framing by avoiding contact with the walls, plus using cheaper no pressure treated wood. It also speeds up the running of electrical.

Greg Di

Those sleepers for the subfloor need to be PT. Unless your basement is SUPER DRY I wouldn't reccomend covering the slab with a plywood subfloor. Any moisture that comes through will condense under there and mold up really quick. Try DriCore panels instead.

heavyparts

I would agree about the walls I don't mind looseing a little Sq Footage its a big basement. ever thought about everthing being true square that helps what would you say for the floor material Size 2x2 or 2x4 ?? Thanks again

go dart

remember to use acq treated bottom plates. note non bearing stud walls extending from the floor slab to the structure above shall be provided with a 1" expansion joint to allow for minor changes in floor elevation. even without a permit this is good practice.

Mike Finley

The flooring part I'm going to have to leave up to somebody else, no experience with that.

Just to clarify about the PT, like Greg said. I'm only referring to the wall framing. If it is off the walls no PT needed in furing strips or direct contact with the walls, but you still need PT bottom plates. Don't forget the fire blocking that will be required also. Here we can use non-craft backed insulation on top of the walls top plates to act as fire block.

bergenbldr

I agree with mike on the benefits of an independantly framed wall system,however i prefer to use light gauge metal framing for basement build outs.Lightwight ,easy to cut, assemble and fire/mold proof.I usally add 2x4 or 2x3 nailers around door window r.o. to simplify installation of wood door frames and trim.Trim head screws are used for attaching baseboards and other trim to metal studs.

Greg Di

WHAT? I've never heard that one before. How are you supposed to make a rigid wall rigid with a 1" gap in it?

Also, if your slab is moving even 1/8", you'd be screwed. All your plumbing connections from water heater, boiler, etc would fail if they were roller coastering on a slab moving like that. Your basement staircase would crack in half too.

I need to hear more about a slab moving 1".

Mike Finley

We have some requirements for that type of wall system out here, it depends on a situation by situation, location by location requirement for bentonite rich soils.

We call them floating walls and they are designed to actually move 1 1/2" or more up and down.

Bascially you connect a bottom plate to the flooring. I say "a" bottom plate because you end up with 2. Then you build a framed wall with a top and bottom plate, but make the wall 1 1/2 too short. Connect it to the ceiling and let it float over the original bottom plate you fastened to the floor about 1 1/2 inches. You line up the two bottom plates and connect them with a 60d nail in every other stud bay. The floor can now raise and fall without effecting the walls.

The base molding is attached only to the bottom plate that is fastened to the floor, it hides the 1 1/2 gap.



It might sound really complex or diffictult to do, but it really isn't that hard at all.

jmic

See, I learn something every day, I've never heard of this either and second everything Greg said. WOW!

Mike Finley

Flex copper lines get sweated in at the ceiling level for hot and cold lines. (Installing Pex would be helpful in these situations too I suppose.)

Fernco expansion joints and rubber couplings are used on the drains and vents.



I should add, all of this is reason enough why a lot of builders for basements are doing wood subfloors that are fasted into the basement walls 18 inches above bottom grade instead of doing slabs in the basements. But when you are talking remodeling on a slab sometimes this is what needs to be done.

Tom R

Here's the complete explanation

http://www.asktooltalk.com/home/qand...ting-walls.htm

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go dart

colorados requirments are as different as their soil. that code is IRC which is used in most areas.

Bukemdano

very interesting read. Does the house footings move as well? If so, does all of them move up and down at the same time as to not crack the walls etc.

I am glad I live where there is lots of sand

Mike Finley

No, the footings/foundation is designed to be extremely stable. Movement in the foundation means you blew it!

Water is the enemy of a stable foundation when dealing with expansive soils, one of the reasons the landscaping plan becomes such an important feature of protecting the foundations out here.

reveivl

I still don't get it, someone is saying that the slab can move vertically, independant of the ext. walls up to several inches? Why doesn't this movement turn the slab into gravel as it rotates up from the walls to the center of the house? Or does the entire pad float up inside the exterior foundation walls?

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Mike Finley

I don't know what you mean by rotating? I'm not following you on that.

But to be really clear here, this isn't designed as a system to deal with a pad moving up and down all the time, it is designed IF the slab moves because you have soil conditions that have the potential to swell due to moisture. Slab movement should be temporary, as in, the f#cking slab moved what the hell do we need to do to stop that???!!!!! Well, if it never moved before it might have to do with the swiming pool you installed last year 4 feet from the house and decided to drain onto the back yard to water the lawn to save water at the end of the year! or, a new buyer of the home rips out the low watered junipers and the wife plants a water hungry bunch of box woods next to the foundation and installs an automatic sprinkler to water them everyday, or somebody digs out around the foundation to repair a porch and doesn't replace all the dirt and grade it downsloping from the house to make sure the water runs away from the foundation, or somebody removes the gutter that were moving water away from the foundation... it moves because you sump pump died this spring... if it is moving seasonally the house is f#cked.

Bukemdano

"somebody removes the gutter that were moving water away from the foundation...?"

I have done that and flooded the basement once

Thanks for the info. I couldnt see the footings moving because like you said... BIg Problems ! Its a pretty cleavor system.

K2

I'm in expansive soil also in Colorado. Cardboard voids in the bottom of wall forms, 10 ft. overdigs replaced with road base and drilling cassions 40 ft deep into bedrock, then setting the foundation on the cassions, are some of the ways we've dealt with our crappy clay. <P>

In Oct of 1982 our area was changing from a 3/4 in. void on floating walls to a 1-1/2 in. void. I was in a engineers office and I explained to him that the old detail on the floating wall would not work for an 1-1/2" void and I sketched out the above detail and said it would have to be something like this. The next week all the local foundation engineering was comming out with my drawing on it. I've always claimed credit for that design of the floating wall, (not that anyone believed me or cared), so if you ever run into that detail dated before Oct 1982 I would be interested in knowing about it.