Insulation between stemwall and porch
whardy7
| Posted in Energy, Heating & Insulation on
I have a rectangular house with a full wraparound porch. The house is on a 3′ stemwall with TJIs and 1 1/8″ decking on top of that. My porch will wrap all the way around the house. It will be 10′ wide and concrete. What should I put between the stemwall and fill sand the porch will be poured on? What will help me the most with insulation and moisture barrier?
Let me know if I have left out some key data and I will add it. I appreciate any counsel.
Wayne
Edited 2/16/2005 8:55 am ET by whardy7
Replies
Greetings whardy7, As a first time poster Welcome to Breaktime.
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someones attention that can help you with advice.
Cheers
"Live Free,
not Die"
Razz,
Thanks so much. I appreciate that. I have been to forums in which there was an "insider system" or unwritten rules that cost you a reply. I was hoping I hadn't already broken one!
If I am posting in the wrong section, maybe someone call tell me what section might be more appropriate.
Thank again for your assistance.
Wayne
Nah, your doing fine here.
Sometimes if a post doesn't get immediate attention it falls off the recent discussions folder and ends up buried in the listed folders where few dare to tread.
You should get some response here today.
If not I'll come back and take a shot at it. ;o)
I spent years around Tulsa and have been thru Stillwater.
There's a couple fellas who post some here some. One named Jaguah and the other Pebbles. They both live there in Tulsa.
"Live Free, not Die"
Edited 2/17/2005 2:59 pm ET by razz
bump
"Live Free,
not Die"
Any takers on this one?
I am confused by the construction and what you are trying to do.It sounds like you are trying to insulate the porch floor?A drawing might help.
Bill,
Actually I am mostly concerned about moisture, then deterioration, secondarily. The fillsand that the porch slab sits on will be against all 3' of stemwall and the 14" wood joist headers. I have been told by some that I need to put some type of insulation between them. But, I have heard several opinions. Having learned a lot on these boards I decided to see what the thoughts were here.
At the same time, I want to insure that my crawspace remains dry and a temperature that does not adversely impact the indoor temperature.
I don't have an easy way to get a drawing attached, but the house is 40'x50' with a 10' covered porch all the way around using trusses that are cantilevered over the porches front and back, then with a Dutch hip on the sides.
Maybe that helps some...
Insulation is usually used to mean a material that is used to inhibit the flow of thermal energy or the flow of electricity.Also a joist header would be something that is used support the joist over a gap such as where a door or window is.I think that you are are talking about what is called a band or rin joist.I think that what you are looking for is a moisture barrier.I would start a new thread and redescribe the problem.
Redescribe the problem? Whatever your definition of insulation, my question is do I need something covering the stem wall before I put fillsand against it? The house books I have call what they put between the concrete/block and the ground "insulation" and "moisture barrier." I was just wondering if I treat a stemwall the same.
For the record, I think it is "rim joist" not "rin joist" :) But, I understand what you mean and will not try to lecture you or make you feel like an idiot for typing the wrong thing, though. I know that how that feels.
Honestly, I appreciate the corrections. I am truly just an ignorant owner-builder trying to build the best house I can. I was hoping there might be some people on the board who could look past that and figure out what I was trying to do.
Do I really have to start a new thread to coax you into telling me what I might use for a moisture barrier, since you think that is what I am looking for (and stated as much in the opening thread?)
Wayne
A 10ft deep concrete slab poured on top of sand that is leveled up to and against the above ground stem wall of the house, thereby creating a porch slab floor extending out 10ft out from the house the entire perimeter of the house, that porch slab at about the same height as the interior wooden subfloor.
Seeing the porch area will be covered, unless you are in a bog area you shouldn't have moisture problems from what I perceive.
A ten foot bank of dirt surrounding your whole crawlspace is kind of like creating a basement. Hot summer sun down there shouldn't heat up the thermal mass of the porch cause it's covered.
If you want to go ahead and spring a few bucks, treat your stem wall like a basement and coat the stem wall with a common asphalt base sealer.
You could call around and find a company that might come out and spray it for you or you could get the stuff and probably roll it on yourself.
Then press 2 inch Dow Blueboard against the sealer and fill your porch base against the foamboard.
What are your plans for ventilating the crawlspace?
be two cents
"Live Free, not Die"
Edited 2/19/2005 10:38 pm ET by razz
Thanks, Razz. That seems to be the prevailing thought - the asphalt rolled on and foamboard next to that. It seems I should do something about moisture, but I agree that since the porch is completely covered it might be an unnecessary concern. I do not have bog problems.
As for the ventilation, I am planning on putting some 2-3 6" pipes on all side to allow air flow. They will go through the rim joists (I think I've got that part straight now!) I have been following the various arguments concerning whether to vent a crawlspace or not, but I have about concluding that the arguments are best for doing so. My access to the crawlspace will be from inside the house.
Thanks, again, for the help. That confirms my direction.
Bill, I will try to learn to describe as well as Razz did in his opening paragraph there! Funny he described my house better than me...
Wayne
You might want to investigate treating the crawlspace as a conditioned area tied to the house instead of the introduction of outside air in there.
If you scroll down in the lower left corner of your screen there is a search function that will take you to previous threads dealing with whatever you type in the search bar.
If you type in 'crawlspace vent' or other keywords of the subject matter, you'll see some data on conditioned crawlspaces pro and con."Live Free, not Die"
"The fillsand that the porch slab sits on will be against...the 14" wood joist headers."Meaning the rim joist (as established in posts 10 and 11).This little point doesn't seem to be getting any attention.Is it sufficient to put a piece of foam board between the wood and the sand??Rich BeckmanAnother day, another tool.
That is what I meant earlier by deterioration. That is not treated wood and seems it needs some protection of some kind.
whard,
Got to wondering about your wrap around porch design. Really like the idea. Practical to the max.
Was this a design from a manufacturer or is it one of your own you decided to add to the 40x50 design.
Is the house already up and completed, at some step in the middle of the building process, or is this all at a planning stage and you are researching, getting your ducks lined up in a row?
Will there be a 3ft exterior concrete wall surrounding the outside perimeter of the porch necessitating entry steps or will there be a gradual sloping down away from the edge of your porch slab?
be wondering"Live Free, not Die"
Razz,
This is my own design. I like the friendliness of it, but the practical benefits are numerous. I am having to do the porches before I can frame because I cannot get concrete trucks to pour the back, so it will have to be wheeled across the decking. There is a 3' fall that demands steps (on all four sides) - I have designed it on Envisioneer (higher version of 3D Home Architect, a great product in my opinion) and like the look of the raised porch. It will have 1' square pillars with white railing around it. I think (hope) it will turn out really nice. Right now I am waiting for it to dry out so I can form the porches.
Wayne
Sounds like a plan.
So the decks done already with non-treated rim joists.
Something's got to be done before you backfill and pour to cover the rim.
I don't have any working knowledge of the norm in a situation like this but shooting from the hip...
Perhaps one could devise a treated plywood thickness to match the thickness of your above ground sheathing, while running the treated ply strips on the band and overlapping the foundation a ways, then sealing it to the foundation with a quality poly caulk.
I'd want a nailer for both the upper and lower sheathing at that seam. Best a double sill plate.
When you purchase the 2" foamboard make sure you get the type made with the anti-bug borates in the mix.
Free Sancho!!!
The seam you are talking about would be on the plate that sits on the decking, bringing this teated plywood (7/16") up to meet the sheathing at that point. Am I understanding that right? The foam board would begin below the treated wood or would go on top of it, as well?
Sounds like a valid plan. I wish it would dry up so I could try it!
Yes, somewhere above the top of the concrete porch depending on where you plan on placing the concrete in respect to the wood decking of the house.
Obviously you wouldn't want the concrete located above the line of the deck. If the concrete is placed at the same line as the subfloor decking then there will be a small step up into the final flooring height via the threshold after the finish floor with underlayment, tile or what have you.
It seems the plan is a flat walkin entry separated pretty much only by the door threshold unless you might desire a small step up in there for a dirt and windblown rains barrier which would mean the poured slab height must be adjusted.
be building
Free Sancho!!!
The slab will be 1" below the threshold with another 1" of slope to the outside. (I want an inch to play with so I have the fleibility of laying other surfaces on the concrete in the future if I desire, such as tile, outdoor carpet, etc. Right now, I am planning on stamping the concrete.) I think I see what you are saying. I'll give that some thought.
Thank you, Wayne
The seam mentioned is the seam created by the two different sheathings, the pressure-treated ply that is to be placed between the slab/sandfill and the concrete foundation/rimband joist, and the normal above ground wall sheathing.
The bottom edge of the above ground wall sheathing which forms the top edge of the seam needs to have something to nail to if you decide to go this route.
I suppose a single sill plate could function as a nailer for both but being it's your own house the cost of a double sill is negligible in the scheme of the whole building.
The placement of the foamboard could go up to the bottom of the slab pour. If you really wanted to get meticulous foam blocks could be cut and placed between your decking joists against the inside of the rim band joist from inside the crawlspace.
The whole idea of foamboard insulation on the concrete foundation is unnecessary if the crawlspace is going to be unconditioned and separate from your living area with vents linking it to the outside.
Then your attention would be to insulating your floor.
The archives have a lot of info discussions on the conditioning of the crawlspace.
You have to decide your approach now before the porch.
be pressured
Free Sancho!!!
Edited 2/24/2005 12:06 pm ET by razzman
Edited 2/24/2005 12:07 pm ET by razzman
Well you got me thinking now so I just reread the thread.
You know, there are rental places in Tulsa where you can get a one yard concrete mixer that you can pull behind a truck.
Concrete companies will fill them and being that much smaller perhaps you can get them behind the house where you said the big trucks can't go.
Seems then you could get on with the program and do the porch deal later.
be...well, you asked for thoughts on the matter
Free Sancho!!!
"That is what I meant earlier by deterioration. That is not treated wood and seems it needs some protection of some kind."I think your concern is valid, but I don't know the answer. Sorry.
Rich BeckmanAnother day, another tool.