Marmoleum flooring ply sub flooring

[bmouthboyo]

hi guys,

I am looking to prep my kitchen / dinning area for marmoleum flooring. Currently have pine planks and have been told it’s crucial the ply subfloor is straight and has feathered edges.

Can anyone explain what feathered edges means? Does it just mean sanding at joins so not proud from next sheet?

Next question is how best to secure it to the pine planks? In all the YouTube videos the Americans seem to use staple guns, same here? Total floor space is about 12m2.

I have an air compressor and was looking to buy a nail / staple gun. Am I right in thinking Ring shank nails are the best for this job or are screws preferred?

Lastly best way to cut the ply? Circle saw?

Never laid a sub floor before so any advice much appreciated.

 

[Deleted member 174758]

Currently have pine planks and have been told it’s crucial the ply subfloor is straight and has feathered edges.

Can anyone explain what feathered edges means? Does it just mean sanding at joins so not proud from next sheet?

It's crucial that you have a flat floor with no protruding edges, fixing heads, etc as this will "telegraph" through any vinyl or linoleum flooring. Similarly any joints in your plywood should not lie directly above joints in the floorboards. It may be necessary to trim sheets to achieve this

Next question is how best to secure it to the pine planks? In all the YouTube videos the Americans seem to use staple guns, same here? Total floor space is about 12m2.

Assuming 9mm or 12mm plywood I'd say my first choice (and the fastest way) would be narrow crown 16 gauge flooring staples on 150mm centres. These are considerably heavier staples than you can apply with a hand stapler and will require either a gas stapler (only Paslode do those - I have one but the price is frankly silly money) or a pneumatic stapler. Note that this is NOT an 18 gauge combined nailer or stapler, it is a far heavier gun using far thicker (wire) staples.

Alternatively I'd use drywall screws (again 150mm on centre), something like 32 or 35mm long. These need to be driven so that the heads are flush or just below the surface, so unless you are prepared to pilot drill and countersink more than 150 fixings per sheet you'll need to look at buying or hiring a drywall screwdriver. These spin the screws at 4000 to 6000rpm which will flush the screw pretty much every time - a 2500 rpm impact driver doing this work with standard drywall screws is very hit and miss and won't flush maybe 5 to 10% (significant if you are doing a lot of screws not to mention slow and frustrating).

An alternative to using drywall screws with a drywall screw gun is to use Hilti "Whiterock" screws with a 2500 rpm impact driver. These are designed to cut their own head recesses and sink flush with slower driving tools, but they won't work well with 1500rpm 12 volt cordless tools - they do need something faster and more powerful like an 18 volt impact driver

Don't skimp on the centres, either, and go to, say, 300mm centres because you think it's a waste of screws. The idea of so many screws is that the plywood sheet is held fairly rigidly and that imperfections in level are mainly dealt with - go too loose on the centres and the plywood can flex under load (and if screeded with SLC, the levelling compound can crack or break-up and then telegraph through your flooring, just like a protruding fastening will). BTW screws don't always work well on 6mm plywood, whereas narrow crown heavy staples do.

Am I right in thinking Ring shank nails are the best for this job or are screws preferred

I'd say not. Ring shanks are probably a bit of an overkill (minimum length 50mm) and with them you are potentially in danger of hitting underfloor pipework or wiring if any of it runs within 25mm of the underside of the floor. In the past when I've tried them out on 6mm plywood they've tended not to sink flush, so I'm not a fan. The traditional way to lay this sort of covering (in 4 or 6mm ply) was to use 25mm flooring tacks, hand nailed. Again 150mm centres (what a pain that must have been)

Lastly best way to cut the ply? Circle saw?

Yes.

Never laid a sub floor before so any advice much appreciated.

Do yourself a favour and do what trade floor layers do - after laying the plywood give it a 2 to 4mm layer of self levelling compound (Bal, F Ball, etc) levelled out with a large trowel. This will take out any imperfections and give you a perfect surface to lay material on. It will also fill any gaps where sheets join and maybe your saw cuts are less than perfect (although you may need to second coat poor joints then rub out with a carbide rubbing brick. Before trowelling this on it is essential that you make sure that ALL of your fixings are flush or just below the surface of the plywood to avoid problems with the trowel striking them and of them potentially telegraphing through in the future

 

[bmouthboyo]

Thank you for the reply JobandKnock, a lot to consider.

I have an air compressor and now acquired a FCN50LHH Tacwise nail gun. It seems it can fire down to 35mm, would this be acceptable for 6mm Ply over 16mm boards?

Is there a 'good practice' we should follow when laying a ply subfloor onto fairly straight soft timbers? Is it the same process as with lyno etc? Bit unsure about gaps needed around edge, how close to door frames etc we need?

Thanks again

 

[Deleted member 174758]

I have an air compressor and now acquired a FCN50LHH Tacwise nail gun. It seems it can fire down to 35mm, would this be acceptable for 6mm Ply over 16mm boards?

Yes, that's the sort of gun you'd find good for this task (150-odd screws per sheet at 150mm on centres means that high volume collated feed fasteners are a must if the job is to be done quickly). We tend to use collated screwdrivers or gas staplers simply because of the test certification issues surrounding the use of compressors and air lines on sites operated by large contractors, although the pull-out resistance of screws is a bit higher than tacks (although not that much)

Is there a 'good practice' we should follow when laying a ply sub floor onto fairly straight soft timbers?

For industrial vinyl flooring (for which the prep is pretty much the same) the sheets are close butted on the floor and run fairly tight up to the skirtings to avoid sunken edges in the lino. If the sub-floor you are laying onto has really low planks in places it may be necessary to build-up areas with 4mm or 6mm plywood in order that the main plywood going over it is adequately supported (it doesn't need to be millimetre perfect, however). "Soft" areas (i.e bits with inadequate support) can give you problems fixing the plywood over cladding down, hence the need to get this support in on bad floors. All protruding fastenings must be driven under the surface before applying the latex. If there are any high ridges (such as where sheets butt together) the plywood might need extra fixings or a bit of adjustment with a belt sander and some coarse belts (P40 or coarser)

In the door openings we run into the opening and finish either half way beneath the door or to the outer edge of the door depending on what type of transition between different floors is required (metal/rubber transition plates, metal profile upstands, etc). How do you intend to transition from lino to whatever it abuts?

Note that in our environment the floorers who put in the vinyl invariably screed the floor with some form of latex (SLC) to take out any remaining discrepancies (e.g. rough edges, joints in boards, low areas, etc)

 

[bmouthboyo]

That's great Jobandknock thanks for the reply.

The fitter came over to do a final price up for the job and is supportive of us doing the subfloor to help keep costs down. He is going to do the final prep in terms of sanding and filling which is good. He actually said to use 4 x 25mm Turbo self countersinking screws so will have to keep my nail gun for another project

Before laying the 6mm Ply over the existing floor I need to sort out an area where I am moving one of my warm air vents and removing another.

The existing planks seem to be 16mm but am finding it difficult to source this thickness ply to fill the area highlighted red above. Can I use 15mm? There will be 6mm over the top of it all so hoping will be OK?

Also is my plan of using cut to shape 15mm ply OK? Reason I thought it best is that the location we are moving the vent to means it would be fiddly to support with replacing tongue and grove.

Hope I am making sense

 

[Deleted member 174758]

He actually said to use 4 x 25mm Turbo self countersinking screws so will have to keep my nail gun for another project

Just thought I'd remind you of what I'd said earlier about ring shank nails, namely, "In the past when I've tried them out on 6mm plywood they've tended not to sink flush, so I'm not a fan." I couldn't see any reference to thickness of plywood in your original post, so I was trying to cover as many of the bases as possible. Details are all

The existing planks seem to be 16mm but am finding it difficult to source this thickness ply to fill the area highlighted red above. Can I use 15mm? There will be 6mm over the top of it all so hoping will be OK?

Offer in a piece first to see what the difference really is (your 16mm might be full, your 15mm bare, so the difference could be a helluva step). If there is a big step it can be taken out by using shims beneath the thinner stock atop the joists where the screws go

Also is my plan of using cut to shape 15mm ply OK? Reason I thought it best is that the location we are moving the vent to means it would be fiddly to support with replacing tongue and grove.

As it will never again be seen where would there be a problem? Yes, it's OK