Home>Discussions>EXTERIORS>New Treated T&G Porch Floor. When and How to Seal it?
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New Treated T&G Porch Floor. When and How to Seal it?

I am about to install a new T&G porch floor. The porch is covered and is located in Iowa where it sees winter and humid summers. If standard (untreated) T&G floor boards are used I understand the need to seal all 6 sides of the unprotected wood. The bottom, tongue, groove and ends should be sealed before installation and the top can be sealed at the same time or after installation. My questions is: When and how do you seal the pressure treated T&G flooring? Most sealer manufactures recommend waiting a few weeks/months to allow the pressure treated wood to dry before applying a sealer. This eliminates the ability to purchase the material and within a few days install it with all sides sealed. )do they need to be

Do I only seal the top and exposed edges of the treated T&G flooring after installation? The bottom will not be sealed and I am worried the wood will be able to expand and contract as it changes water content from the dry winters to the more humid summers. Will this be a stable material since it is treated?

Do I need to purchase and set out the T&G flooring, uninstalled, to let is dry, then seal all sides, then install it? I am afraid during the drying time the boards will warp and twist and my current schedule does not allow for this drying time.

Or should I use the untreated material to be able to seal all 6 sides right away and install it?

Any direction on material choice and sealing method is welcomed. At this time composite and PVC materials are not an option at 6 times the wood cost. I cannot justify the cost compared to maintenance and replacement of wood.


Re: New Treated T&G Porch Floor. When and How to Seal it?

Lumberyards will usually sell 'premium grade" material for this though they don't often stock it. It is shipped partially or completely dry and is made from better grades of lumber. The fully dry pine may be prone to fastener splitting; I generally add 5-10% footage to compensate. For T&G floors it's all I will use outdoors. If you can get to the bottom after installation a garden sprayer can make short work of waterproofing there. Most sealers will specify a specific permissible moisture content and electronic meters are made to measure this, but most folks just wait a month or two and make a good guess about when it's ready. Keep the top resealed as needed and do the bottom every other time for maximum life, not much you can do about butt-jointed ends.


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