With concrete holding the moisture against the wood, wood has no chance and will eventually lose the battle. Now you don't have to lose all hope because it's for certain that the concrete around the post will crack, therefore making it easy to pull out when it starts to rot. Even worse, the concrete cracks early.
The bad stuff seeps downward right into the “Hot Zone”. Mix in some oxygen, the moisture from below, the fact that concrete holds a constant temperature and moisture, and those wood posts are going to prematurely rot. No exceptions.
Wood in direct contact with concrete, and the dampness often found there, will rapidly decay. To avoid this, use pressure-treated lumber.
Boric acid (borate) is one of the most effective fungicides for use in treating wood rot. It can be applied to wood during construction to prevent future rot, or as a treatment to stop an active decay fungus from growing.
Concrete will allow water or water vapour to move through it quite easily, so any wood in contact with concrete must either be pressure treated wood, or you should have a plastic separator between the wood and the concrete.
Adequately sealing the space between the concrete and wood must include an application of a quality sill plate sealer, like TERM® Sill Plate Barrier, and a quality fluid-applied flashing for the interior and exterior joints, like Polyguard Blue Barrier Gap Filler.
We recommend mixing authentic pine tar with purified linseed oil. These two products can work well to ensure the wood substrate is properly nourished. They can protect the wood against rot and damage. The treated wood can also deter insects.
You can use three main types of treatment on ground contact wood: silicate preservatives, phenol-formaldehyde (PF) preservatives, and copper-based preservatives. However most of these you can only get these from lumber that's already treated.
White vinegar will stop wood rot
Because it is a fungicide, which has antimicrobial properties. As wood rot is caused by fungi that require an acidic environment ranging from 0-5.5 (pH), white vinegar solves the problem by changing the pH level in the wood.
To keep the concrete from sticking, treat the wood with a release agent. Some lumber mills pre-treat the wood with an oil-based blend to make it stick-resistant. Otherwise, apply a release agent to the boards before building the formwork.
You can use overlays to create concrete surfaces that run up wood walls. Overlays are also used down wood stairs, over wood countertops, and — more often than not — across wood floors or decks. The substructure must be well construction to successfully support a cementitious overlay.
Whether you're building a fence, setting a mailbox or even a basketball goal, the best way to ensure your posts will stay sturdy and true for years is to set them in concrete.
Although wood is a cheaper alternative to concrete, it ages faster and has higher maintenance and repair costs. Hence, while wood deteriorates quickly, especially if it is not maintained regularly, concrete has a lifespan of two to three times more than that of most other building materials.
With concrete holding the moisture against the wood, wood has no chance and will eventually lose the battle. Now you don't have to lose all hope because it's for certain that the concrete around the post will crack, therefore making it easy to pull out when it starts to rot. Even worse, the concrete cracks early.
While pressure treated poles can stay up to 40 years without any signs of rot or decay, decks and flooring might only last around 10 years.
While a treated 4x4 may last 10 to 25 years, depending on the wood, the soil, and weather conditions, following the simple steps below could double or triple that number. By comparison, an untreated wood fence post may need replacing in as little as five years.
Wood can Start to Rot in 1-3 Years If:
Wood is untreated. The wooded area is in a hot climate. The wooded area is not painted with the proper paint.
Some say that untreated 2×4's can last up to two years before showing signs of rot and others say it can last even longer. When deciding if you should you use an untreated 2×4 it depends greatly on the application, how much weather and sun it's exposed to and if it's making ground contact.
I recommend using an exterior silicone formulation for concrete or a high-quality polyurethane sealant. Both will stick well to the wood and the concrete. Acoustical sealant is a better, albeit slightly more expensive, option. Caulk often works best at a slab-wall transition.
While the advantages outweigh the negatives, there are some disadvantages that you should keep in mind before sealing your concrete driveway. Sealant can make the surface slippery. Sealants tend to dry down with a glossy or semi-glossy sheen that can be quite slick, especially when wet.
You need a poly vapor barrier over the concrete, then sleepers under the sub-flooring upon which you install the wood flooring. You can use rigid foam between the sleepers, if you want a warmer floor. Technically there should already be a vapour barrier below the concrete.
If you have sidewalks or driveways of a certain age you have these--wood expansion joints! These are important as they allow the concrete to expand and contract without cracking. Unfortunately, time and the elements take their toll on them. Eventually they rot and break and should be replaced.
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.