Is this marine plywood (B&Q)?

Possom

leveller2911 wrote: »

18mm Marine ply too thin?.......... Marine ply won't have voids in it and as long as the floorboards underneath are fix down properly and the ply is fixed every 200mm or so it will be more than adequate , 18mm won't be flexing if the subfloor and ply are fixed down correctly.


Certainly don't need 25mm Marine ply for a bathroom floor .

andyhop wrote: »

In previous posts by the OP, he was on about removing the floor

18mm is too thin for a new floor, 22mm yes but you'll struggle to find a timber yard that stocks in marine

I am to remove the floor. (Perhaps new pine floorboards should be put down and the marine plywood on top?).

So why is 18mm thick marine too thin? The original 1930s pine floorboards are 18/19mm thick.

glubalub

The biggest issue is with the strength and stability of the joists. Any flexing of the floor may lead to tiles popping even if a flexible tile adhesive is used. The easiest way to check for stability is to jump up and down on the mid span of the floor and see if it flexes.

BS 5385-3:2014 for normal conditions states that a ply substrate for a new floor should be at least 15mm thick which is not a common thickness for ply so 18mm is generally used instead (glue bond 3 BS EN314) and fixed at 300mm centres which is likely to mean lots of extra noggins. It also suggests that if in doubt, the 15mm ply is overlaid with broken bond 10mm ply. The underside and edges of the ply (but not the top face) should be sealed with varnish.

Possom

glubalub wrote: »

BS 5385-3:2014 for normal conditions states that a ply substrate for a new floor should be at least 15mm thick which is not a common thickness for ply so 18mm is generally used instead (glue bond 3 BS EN314) and fixed at 300mm centres which is likely to mean lots of extra noggins.

So 18mm thick marine plywood (with no subfloor to which it's attached - just joists), is okay for a bathroom floor?

andyhop

It's too thin as a stand alone floor.

You need 25mm

There will come a time where I'll just pass on your posts, you seem to take zero advice

Possom

andyhop wrote: »

It's too thin as a stand alone floor.

You need 25mm

There will come a time where I'll just pass on your posts, you seem to take zero advice

I'm not sure why you've made that comment.

You suggested the use of marine plywood for flooring (a product I had never heard of), which is why I am interested in using it.

You suggested the use of Homelux matting over plasterboard instead of Hardibacker plasterboard which is why I've bought Homelux matting.

glubalub appeared to suggest that 18mm plywood is okay for flooring, which is why I asked for clarification from glubalub.

I'm sure no-one expects anyone on MSE to simply accept a suggestion without asking a few questions.

keith969

andyhop wrote: »

Sheet of 18mm marine plywood, to trade £35 plus vat

Do tell us where. It's £68+vat for a single sheet at the local timber merchants, or £50+vat in 50 up quantities...

andyhop

Rembrand timber. Platinum grade marine

25mm is £56 plus vat

Based on any sheet volume - used the same timber supplier for over 10yrs

andyhop

Possom wrote: »

I'm not sure why you've made that comment.

You suggested the use of marine plywood for flooring (a product I had never heard of), which is why I am interested in using it.

You suggested the use of Homelux matting over plasterboard instead of Hardibacker plasterboard which is why I've bought Homelux matting.

glubalub appeared to suggest that 18mm plywood is okay for flooring, which is why I asked for clarification from glubalub.

I'm sure no-one expects anyone on MSE to simply accept a suggestion without asking a few questions.

You lack the very basics in theory and show no practical ability , before you cause serious damage to your property and cost yourself a fortune I'd employ the services of a experienced and trained operative :beer:

Possom

andyhop wrote: »

You lack the very basics in theory and show no practical ability , before you cause serious damage to your property and cost yourself a fortune I'd employ the services of a experienced and trained operative :beer:

I'm not going to do the work myself. I'll buy in many of the products required. Such as the Homelux matting, and I'll get a professional to install once I've done the necessary research.

I could just ask a professional to install what they preferred without doing any research myself, but they could have one of a number of opinions (such as wanting to use hardibacker instead of Homelux matting). Or putting down pine floorboards, not marine plywood.

Doing the research myself in advance means I can converse with whomever I employ to do the actual work in an educated manner.

southcoastrgi

Different installers will use different products, as I've said I personally would use hardibacker over homelux, but something like the thickness & stability of a floor to accept tiles is a pretty standard thing