DO YOU SEAL NEW PLYWOOD

[Walkingthedog]

I just sloshed on any old emulsion I had for the first coat then added a home made grotty colour.

[Chippingford]

I haven't sealed mine either as it's in the comfort of my dining room

[Walkingthedog]

Still worth sealing both sides and the edges. Mine is in the spare bedroom but sealing it was the first thing I did.

[teedoubleudee]

Personally I don't see the point if the layout is in a centrally heated home. I painted the topside with emulsion but for landscaping reasons. Nothing on the underside. If your layout is in the loft or an unheated outhouse different story.

[Dave S]

Yes. Both sides if possible. White emulsion is good underneath makes things easier to see. As for the top I just slosh on any emulsion paint I can lay my hands on. Usually mix some bits up to make a gungy browny grey.

Sealing the wood wasn't on my ever increasing list of jobs, but I do like my electrics neat and to make things easy on myself when revisiting later and likely forgotten how I did things.
Also, I hate to throw old paint away, so that's a very green solution for the top..or brown...or grey.. ..or Teal to match the interior decor don't you know.

[Mountain Goat]

It all depends on the enviroment one needs to use it in. My Dad used to tell me about different types of wood. How some were living and some impregnated woods were dead and there was no life in them. I can see what he means. My Dad did not like using this "Dead" wood even though we all know what the manufactures are trying to do to make it last.

But when it comes to sheets, if there is dampness then they will warp if they get damp and have any weight on them, so in this enviroment they need a coat of something which stops wet getting in and yet allows the wood to let any wet inside it out which is why baseboard tops and sides maybe painted but the underside left. One could pint the lot but if moisture did find its way in it can become trapped inside the wood.

We have all seen cars with water bubbles trapped under paint or wood that rots inside its painted surface... So it maybe an idea to paint the exposed upper sides... Just a thought.

Sadly my Dad passed away so I can't ask his advice as he had been in the carpentry trade all his working life and still kept his enthusiasm up for his line of work.
I was thinking the other day when we visited his grave and was looking at the others around there like my grandmother a few graves up and my first boss the next line across and all the others who had died... How people spend a lifetime of gaining knowledge and experience and then they die and the next generations start again from scratch doing the same and asking myself why? Why do the young not want to listen and think they know better? Why are the old not able to pass on what they have learned? It is a thought which makes me ask what life is all about? What I mean by this is "Do we have to learn all this stuff because it is relevent to what comes next in the afterlife?"

Anyway... Back to wood.

If in a dry house it does not matter so much but in a shed or an outhouse etc it is a good plan to give it a protected coat on the top and sides. Not sure if treating the underside. Maybe a light coat if used in a very damp enviroment?
But one is usually coating the wood with paint when it comes to scenery anyway. I learned te easy trick when I was thinking to myself "Why am I glueing down the scatter or flock etc when the paint is sticky and will stick all this stuff as it dries, so from then on I got green or brown or whatever colour groundcover paint and dropped the flock or scatter to the surface of the paint before it dried and it worked well. Any exposed areas one has missed one can always use spray glue and add more flock or scatter?

[Dave S]

Now there is wikipedia but that is still inferior to hands on experience.
The paint breathing thing also applies to stone, with National Trust finding the extra good plastic masonry paint caused it to sweat and lift the paint.
Old methods were better.
Handing on knowledge to children is the way of business (..& son) and also in the wildlife kingdom.
And isn't that what this forum does - Pass on specialist knowledge to those with like passions.