Home>Discussions>EXTERIORS>new decking over old?
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onthewayhome
new decking over old?

My 10' X 10' deck has 2X4's laid with the 4' up with about 1/2" spacing that is in fairly good condition. I want to lay "Weathershield" 5/4"x6" premium pressure-treated decking over the 2X4's. I will lay the new decking across (not parallel) the existing 2X4's. Should I lay the new decking directly on the old or should I cover the old with an underlayment like lauan plywood? Also, how should I attach the decking - adhesive with screws or nails or what? What should the spacing be between the boards? Thanks for your reply. Bob

MLBSF
Re: new decking over old?

to add to Jkirk's correct answer, why was the existing floor made from 2x4's in the first place? never heard of that one before. if you're going to do it, do it right. remove all the 2x4's and put proper decking down on top of the joists. covering the 2x4's with plywood is worse than just putting new decking on top of the 2x4's.

onthewayhome
Re: new decking over old?

The 2X4's were there when I bought the house and were painted. I have put indoor/outdoor carpet but it is wearing out. The deck is covered so its not subject to much weather or sun. If I remove the 2'X4' decking the new would be below grade and the joists would have to be raised. Its a real problem! Bob

peterbouchard
Re: new decking over old?

Do you mean that the step up to the house/flooring would be greater than code? Not sure I'm understanding below grade...

Tony
Re: new decking over old?
onthewayhome wrote:

The 2X4's were there when I bought the house and were painted. I have put indoor/outdoor carpet but it is wearing out. The deck is covered so its not subject to much weather or sun. If I remove the 2'X4' decking the new would be below grade and the joists would have to be raised. Its a real problem! Bob

If the joists are ok, why can't you rip 1 1/2" X 1 1/2" strips for on top of the joists (furring) then screw the decking to that? It will give you what you want without adding all the extra lumber that will just cause problems later (as was mentioned by J.Kirk and the others).

Calcats ;)

onthewayhome
Re: new decking over old?

Thanks to all who replied. Since I am 77 and evidently I would have to rip out all of the existing 2'x4's and replace it with new decking I have decided to repair the existing decking and next spring replace the indoor/outdoor carpeting. Bob

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