You should always have a barrier between any wood and concrete, specially if the concrete is freshly poured. The wood will soak up the moisture from the concrete and the wood will rot. Pressure treated wood is more resistant to rot but over time, it will have the same effect.
Pressure-treated wood is required whenever you attach framing lumber or furring strips directly to concrete or other exterior masonry walls below grade. Note that this requirement is only for exterior walls, as these may wick moisture onto the lumber.
Pressure-treated wood and concrete are two commonly used building materials for exterior applications. However, setting the wood in concrete may create a situation that speeds wood rot. Pressure-treated wood will rot in concrete when exposed to wet conditions such as trapped water.
Wood rot happens because of a combination of moisture and fungi. In order for fungi to set up shop, the wood must remain continuously damp; fungi will not grow on dry wood. If the wood inside the concrete is located and housed such that moisture can get inside it and stand for a length of time, then it will rot.
Purchase a wood preservative that contains copper naphthenate at a lumberyard or hardware store. Pour about 1⁄2 litre (0.53 qt) of it into a large bucket. Set the end of your post that you'll bury in the ground into the bucket and let it soak for 15–20 minutes.
But when it comes to the basement, you may be wondering if it's possible to install hardwood flooring directly on top of the concrete. The short answer is yes; but be sure to talk to the experts before making a final decision.
After pouring and finishing the slab, you should wait 24-48 hours before removing concrete forms. You can remove the formwork once the concrete has enough strength to keep it from cracking. Concrete naturally contracts as it cures, so it should pull away from the forms and make them easier to remove.
Uncoated wood is routinely used to make large molds for curbs and house footings. After curing, the concrete will unstick from the wood relatively easily. But using wood coated with a slick surface will make the release even easier.
You need to add gravel to the bottom of your post holes. Using the dirt from the hole you dug works just as well as using concrete. Concrete over time will rot out wood post. Once the post are set in concrete, you need to brace each post for several days while the concrete cure.
The problem with concrete is that it is porous. It soaks in the moisture from the air and the ground, so it is not the best idea to place solid wood installations over concrete. While wood won't react with low moisture levels, higher ones can cause wood to swell.
Untreated lumber, such as pine, is the least durable . It will warp and begin to rot within three to five years. Cedar and redwood are naturally resistant to both rot and insect infestations, which is why they're often used for decks and fences.
As a whole, the post and lumber specimens indicate an expected durability of over 50 years for creosote-treated wood and over 60 years for wood treated with pentachlorophenol, copper naphthenate, ACZA, or CCA.
Use pressure treated wood in any situation where there's direct contact between the wood and anything that could supply moisture. This means posts in contact or buried underground obviously, but it also includes any lumber touching concrete or masonry since it's porous and wicks water like a sponge.
Both solid wood flooring and engineered wood flooring can be laid onto a concrete subfloor.
Permeable Polyguard Blue Barrier Gap Filler is a structural adhesive and detail sealant that is used to fill gaps and bond dissimilar materials like concrete and wood. Builders can use Joint Filler 2200 to seal the interior and exterior gaps between the foundation and framing.
Petroleum Jelly is a "Vaseline" type of paste release agent. Ideal for use between concrete and formwork, can be applied with cloth or brush or can be rubbed on by hand. Petroleum Jelly can be thinned with White Spirit, if a more liquid release is required.
The hardening, or curing, continues as long as moisture remains in the concrete. If too much water is lost from the concrete through evaporation, the hardening process slows down or ceases.
Virtually any "Exterior" rated APA panel can be used for concrete formwork because all such panels are manufactured with moisture resistant adhesive. For concrete forming, the plywood industry produces a special product called Plyform®, which is recommended for most general forming uses.
After initial installation, how long do I need to wait until I can walk on the concrete and/or place furniture on it? After initial installation, wait 24 hours before walking on the concrete and then wait another 7 days before adding furniture, flower pots, etc.
The floor manufacturer recommends placing a 6-10 mil plastic sheet over the slab to prevent water vapor from damaging the engineered hardwood.
The concrete slab should be level within ⅛” over 8-10 feet, which is standard for hardwood flooring. Then, we recommend covering unsealed concrete with 6-mil polyethylene fabric to block moisture from wicking up the concrete to the hardwood floor.
Therefore, because concrete is porous, it's a good idea to install a vapor barrier over your concrete subfloor before installing your flooring. This way you can stop the vapor drive of water upward to your floors, protecting them from any damage (source).