pouring concrete around cedar post
BillWemyss
| Posted in Construction Techniques on
I`m building living space in a barn.Can you pour concrete around cedar post?Also what about vapor barriers on walls and ceilings?I’m building stud walls,insulation and dw inside barn.Has metal roof.will that sweat on my ceilings?Will outside walls need sheathing or vapor barrier?if so how will you get that on walls if you build them right next to barn walls (board and batten) ?
Replies
fill out your profile. Where you live has much to do about how we answer.
middle Tennessee
I would paint the wood surfaces first, where the concrete touches the wood.
What happens is, the water in the cement swells up the wood. After the concrete drys out, the wood shrinks and leaves a gap.
If the wood post is touching soil, NO! Well, you could do it but it's not good practice in the art. Best bet is to get it up off the concrete on a Simpson PB of some sort then place your concrete around the base or, support the load, place the concrete and then build up from PT wood base.
Best not to pour concrete directly against the post -- place some barrier such as a piece of the tarpaper-like joint board against the wood first. Concrete is hydroscopic and conducts moisture into the wood if given half a chance.
In some cases it might make sense to cut the post off so you can elevate it above the concrete on a metal spacer, but this shouldn't be done if the building is a pole shed since a pole shed relies on the stiffness of the post in the ground to prevent racking.
Where you are it's probably just as well to not use a vapor barrier (except under the concrete). Instead cover the back side of the studwall with housewrap or some such to reduce air infiltration. (Build the studwall on the floor and lift it into place after covering it.)
I wouldn't expect condensation on the metal roof (except perhaps on the coldest day of the year) unless you have some moisture-producing activities inside. This risk can be further reduced by ventillating the attic area somehow.
You are right on if he is pouring the complete floor of the barn. Most of the moisture condensing inside a sheet metal barn roof comes from wet soil inside the barn. A vapor barrier on the ceiling might be adviseable to keep any interior generated moisture (cooking, showers, etc) from getting to that cold steel.
Edited 5/27/2008 4:13 pm ET by DaveRicheson
When pouring concrete around embedded posts, wrap the posts. I have used 1/4 inch thick fanfold insulation ( left over from a vinyl siding job)...I fold it around and use duct tape and some staples to hold it together. I have also used both 30lb felt paper, and asphalt based window /door wrap ( peel and stick stuff) with no problems.
Wrap posts higher than you plan to pour. Afterwards, remove exposed wrapping using a razor knife. Cut the wrap even with or (better yet) slightly below pour height. Then, caulk around post using urethane caulk such as NP-1 or similar product.
Best to lay down plastic on floor as a vapor barrier prior to pouring floor....This will help stop moisture from coming up thru concrete.
Davo
Hey, just curious. I used to live in Murfreesboro...where you at?... Springfield, Nashville, Franklin, Lavergne, M'boro?
Got a buddy who resides in Franklin. Visited him 2 years back...man that area has really grown up...I didn't even recognize M'boro anymore. That's some nice country.
Davo