gaps in subfloor

[dotto]

Hi all.
I want to tile the floor of my bathroom, remove existing floorboards and put down 25 mm plywood and tile on the top of it.
When i screw down plywood, do i need to leave a 2-3 mm gap between the joints or do i need to leave a 2-3 mm gap just around the perimeter of the room? Should i need to leave a gap between joints, how can i prevent the glue from filling the gaps? Thank u for your time

 

[noseall]

you don't need gaps with a plywood sub floor. it is not ''real' wood or 'live' wood and so does not behave like it. it will not expand or contract an awful lot.

 

[mattysupra]

make sure you leave plywood in or next to room to acclimatize for 48 hrs prior to laying and then you should take moister reading of joists / floorboards your laying over and make sure they with in 4% of each other! if not leave for longer then you can butt joints together.

 

[dotto]

you don't need gaps with a plywood sub floor. it is not ''real' wood or 'live' wood and so does not behave like it. it will not expand or contract an awful lot.

Thank u all 4 advice

 

[gcol]

make sure you leave plywood in or next to room to acclimatize for 48 hrs prior to laying and then you should take moister reading of joists / floorboards your laying over and make sure they with in 4% of each other! if not leave for longer then you can butt joints together.

I agree that it's a good idea to let the ply acclimatise matty. However, this isn't really possible if you do this type of thing for a living. I mean, it's not practical to pick up the ply, drop it off at the customer's house and come back a few days later to check the moisture content. You could have the wood delivered but that means that someone needs to be at the property to accept it and move it inside. Having said that, for the diyer, there's no real hassle involved with storing the wood for a few days.
Regarding the moisture meter, I think you're leading the poster a little up the garden path. Only a good moisture meter will give you the kind of detail (4%) that you seek (especially in a pretty dry house) and that's gonna cost big bucks. This isn't really an option for the home diyer and in my opinion, unless you have reason to believe that either the ply or the joists are excessively damp then I'd say you'd be wasting your time and money.
gcol

p.s. Good post on levelling a wooden subfloor.

 

[mattysupra]

make sure you leave plywood in or next to room to acclimatize for 48 hrs prior to laying and then you should take moister reading of joists / floorboards your laying over and make sure they with in 4% of each other! if not leave for longer then you can butt joints together.

I agree that it's a good idea to let the ply acclimatize matty. However, this isn't really possible if you do this type of thing for a living. I mean, it's not practical to pick up the ply, drop it off at the customer's house and come back a few days later to check the moisture content. You could have the wood delivered but that means that someone needs to be at the property to accept it and move it inside. Having said that, for the diyer, there's no real hassle involved with storing the wood for a few days.
Regarding the moisture meter, I think you're leading the poster a little up the garden path. Only a good moisture meter will give you the kind of detail (4%) that you seek (especially in a pretty dry house) and that's gonna cost big bucks. This isn't really an option for the home diyer and in my opinion, unless you have reason to believe that either the ply or the joists are excessively damp then I'd say you'd be wasting your time and money.
gcol

p.s. Good post on levelling a wooden subfloor.

all i can give is advise on the correct method. Wether or not you chose to take a risk and not follow the rules its your own fault if it fails. Using a meter to test speeds up the install. You can test to see if you can fit straight away! But for a diyer just leave to acclimatize and then you know your safe.

 

[noseall]

arguments for both sides make sense, particularly after reading this,http://www.umass.edu/bmatwt/publications/articles/detailing_for_wood_shrinkage.html especially the bit about 'When panels bow'.