Hi All, I found this site last week and I have been browsing through loads of posts looking for some advice on overlaying the original T&G floorboards in my house with plywood sheets however I feel like I've now got more questions than before I arrived. I've got a Bedroom, Living Room, Kitchen, Hall, Porch and Bathroom all to do (all on the ground floor) although the Bedroom is the current project. The existing floor boards are in good condition although the floor has been opened up in quite a number of places at one point or another and some boards have partially split when its been removed so my thinking was to put down plywood sheeting to provide a fresh smooth surface. I've previously put down 4mm hardboard in upstairs bedrooms secured with Spax screw's, this worked fine in 1 room but in the other it started popping up in areas even though the sheets had acclimatised for weeks (again I used a ton of spax screws but I guess it wasn't enough). In retrospect I think using hardboard was a crap idea hence why I'm looking at Plywood (specifically 9mm thick). I've not yet decided what the bedroom floor finish will be yet, it was previously carpet but I'm beginning to consider laminate or perhaps vinyl. I was all set to place an order for Dressed Timber/Plasterboard/Plaster and Plywood from a local builders merchant when I thought I better check with professionals if the 9mm plywood is suitable/overkill/not enough etc... hence why I am here . So, after an hour or so browsing through topic after topic on plywood last week, I started to read about stuff I hadn't even considered: Plywood Type: I learned that there appears to be 2No. standards of flooring grade plywood you guys prefer to use: FG1 & SP101. I've never heard of either but I'm wondering if they are only required for specific floor finishes or always used regardless. I don't even know anywhere local I could get the stuff from and doubt any of my local builders merchants stock it, though they do stock: CDX Sheathing (softwood) MLH (Mixed Light Hardwoods) EN636-2 Performance EN636-3 (S) (Marine plywood alternative) Screeding: I'm unsure if this is needed as a substrate for specific floor finish or only required if the floor is uneven. I'm hoping not to have to do this as I don't have any issues with high/low spots. Feathering: I had to google to find out what this meant. Again I'm not sure if this is something I will need to do or not? Fixing Methods: As mentioned above, I normally use Spax screws as they seemed to be the best gripping screw. Is there a superior screw that you guys use? Also, do you advise glueing boards down or is mechanically fixing enough? Apologies if the above is a bit War and Peace, I just don't want to be forking out for the wrong products and I figure you guys are the best to ask. Cheers
It all depends on what floor finish you want, if it’s something to be bonded down you will need sp101 or fg1 if it’s a floated floor or carpet you will get away with standard sheeting ply. Fixings should be spaced at a maximum 100 mm centres around the perimeter of each plywood sheet, 12 mm from the edge and at a maximum 150 mm within the sheets. Either use countersunk screws or ring shank nails, any bonded floor should have the ply joints and screw holes feathered at a minimum ideally you would prime and over screed with a fibre reinforced compound, ceramic tiles and natural stone you will need 15mm ply overscreeded with a depth of 10mm. Sent from my iPhone using Tapatalk
