bowed floor boards

[davediy]

I've just removed some old - 40 year old- thermo plastic floor tiles and the backing bitumin layer . I need to level the floor ready for the floor cover. Haven't yet decided but the wife fancies amtico tiles. I was intended to cover the floor with 6mm wbp ply nailed at 150mm centres but notice the floor boards are bowed across their width by 1mm and in a couple of places up to 2mm. I intend to screw down the boards before nailing where the nails have popped up but suspect the bow is there to stay. Will the ply take care of the bow or should i make some attempt to level first. All the boards are firm and don't appear to move when you walk on them. Any advice welcomed.

[Sir Ramic]

Why not use Mapei Fibreplan self leveling compound ?

[theyomper]

Run an electric planer over the bowed part of the boards. If using Amtico you really need to get the floor as flat as possible.

[davediy]

Thanks I'll try the planer first and the leveler if that fails. When i'm using the leveller presumeably i will need to bung up holes in the floor roung pipes and where the tongue and groove has been cut to get to pipework etc. Wiil the leveller be ok when i bash nails thru to fasten the ply down?

[grumpygrouter]

Better off screwing your ply down.

[doug boardley]

as Grumpy Grouter says, make sure your wbp is well screwed down mate.

[tfs]

It is common practice for floor layer to nail there ply down and also feather finniosh the joints between every sheet of ply to prevent the joins becoming visible through the flooring at a future date. You can use STOPGAP 500 MICRO a brand by Ball.

As mentioned by someone else I too would try to level floor first. If you have a Belt sander you could also use that to sand down any high level in the floor. For low level you could place packers on the underside of the floor board to raise them up to level with the rest of the floor.

If working with a design vinyl be sure to go over the floor covering with an 80kg roller in both directions across the floor.

Any dips, joints etc can be seen a mile away in this type of flooring. I have installed it previously in the full downstairs of my home and can see a few imperfections in my hallway.

Also if you want a little extra peice of mind you can use a glue on the underside of the ply such as no nails, grip fill or something like that to achieve a better grip between the ply and floor.

[mikethetile]

i would over boarrd

im assuming that as the house is 40 yrs old the boards are no wider than 150 mm

hence the high spots are @ 150mm centres so screw down on the high spots

[FreeD]

I'm working on a job at the mo with floorboards that are in a very bad condition...bowed and damaged...i replaced damaged ones...then secured all boards with 50mm turbo screws into joists...(watch out for pipes/electrics) overboarded with 12mm ply using almost a tube or no nails on each one to take up the voids..screwed ply down with 25mm turbo screws...still not level going to screen with mapei fibre plan on monday.

Is it possible to remove the boards and screw down 25mm ply?

I would imagine trying to get boards level again with plane/sander etc is going to be a messy and time consuming job with no gaurantee of good results u'll probably have to take each floorboard up.

[tfs]

I'm working on a job at the mo with floorboards that are in a very bad condition...bowed and damaged...i replaced damaged ones...then secured all boards with 50mm turbo screws into joists...(watch out for pipes/electrics) overboarded with 12mm ply using almost a tube or no nails on each one to take up the voids..screwed ply down with 25mm turbo screws...still not level going to screen with mapei fibre plan on monday.

Is it possible to remove the boards and screw down 25mm ply?

I would imagine trying to get boards level again with plane/sander etc is going to be a messy and time consuming job with no gaurantee of good results u'll probably have to take each floorboard up.

it is most likely to be the joists too that are contributing to these problems so packing under the floor boards would be best option. You could patch screed badly sunken areas before you sheet over with plywood.

Prime the floor fist with a polyurithene primer.

Ball have the STOPGAP range of adhesives, primers, Screeding compounds and chemical dpms. Check out there website for info on products. You can pick these products up from local flooring distributers.

[davediy]

It had crossed my mind to take up the tongue and groove and put down chipboard flooring even before i noticed the bowing - there are a couple of places with odd holes and roughly removed/replaced boards. I need to do something like that under the toilet where the floor boards are a bit rank. Is 18mm wbp ply thick enough in place of the floor boards and is it better than flooring chipboard.

[tfs]

It had crossed my mind to take up the tongue and groove and put down chipboard flooring even before i noticed the bowing - there are a couple of places with odd holes and roughly removed/replaced boards. I need to do something like that under the toilet where the floor boards are a bit rank. Is 18mm wbp ply thick enough in place of the floor boards and is it better than flooring chipboard.

Mate, the floor bords will not be the main problem. In most cases the joists may also have warped or sunk etc due to movement, moisture and movement as expected over time so laifting floor board and sheeting with ply is not neccasseraly the best solution. If the prep work is just for Amtico or Karndean etc, then you realy just need to make the existing floor level. You can acheive this by sanding down or filling and dips etc with a screed and then sheet over the area with 6mm ply you were inttending to use. Just remeber to prime before screeding and feather finnish any joints between the board of ply.

With the right products this will be a faster way to do than ripping up all floorboards and then sheeting with 18mm ply. 18mm ply is not a cheap option and after screwing you will prob still find that the floor is not flat. Some old floor boards may need replacing but I wouldnt replace them all if it was me.

I have experience in this type of flooring and have been employed in the industry and the ways I have mentioned were used with success.

Design vinyl does not require the absolute stabilty that ceramic and stome do as it will not break and crack the way ceramics will.

[davediy]

right thats it then plane, leveller, screw down 6mm ply feather gaps.
Thanks you all for your help and patience.

[tfs]

right thats it then plane, leveller, screw down 6mm ply feather gaps.
Thanks you all for your help and patience.

Anular ring nail are suitable on this occassion mate lol they will be much faster too.

[FreeD]

tfs have to check out f ball tech...

so tfs you would screed first before overlaying with ply? what self leveling compound would you recommend to go directly onto the floorboards?

so have i done mine the wrong way round! would have thought it was quicker to ply first...what with all the gaps to fill between floorboards

[tfs]

tfs have to check out f ball tech...

so tfs you would screed first before overlaying with ply? what self leveling compound would you recommend to go directly onto the floorboards?

so have i done mine the wrong way round! would have thought it was quicker to ply first...what with all the gaps to fill between floorboards

I am in no position to say you did it wrong mate. Do it whatever way you believe is best.

I meant patch screeding (just dipping areas) if you were to screed over the ply there would be no need to screed full area either but, if you screed over the ply I would be worried about the screed failing to bond good enough to the ply and worst case scenario it could cause a tile or plank to lift from the floor. As for screed falling through gaps, gaps are usualy not that big between boards and tend to be filled with debris. After priming they would most likely be sealed.

If you patch screed under the ply it sorts the uneven areas of the floor and is then sheeted over and you get a direct bond to the ply.

i CANT SAY AN EAXCT TYPE THAT i WOULD RECCOMEND FOR THIS BUT, STOPGAP RANGE AND TWO PART LATEX SCREED. The website will advise on the best ones. They have a very good range. F Ball - The First Choice for Flooring Professionals - Product Search

[doug boardley]

certainly from a ceramic tiling point of view, ply overlay screwed, then slc if needed!!

[tfs]

certainly from a ceramic tiling point of view, ply overlay screwed, then slc if needed!!

I can only imagine that products for tiling trade and those for the flooring industry have been made to work with materials in there own industry. I dont know if screeds used for flooring could meet the same requirements as those used for tiling.

Just the way its done in the flooring game. Just as PVA is suitable for priming some surfaces but, as we have alll read on here its not suitable for priming priot to tiling. lol

Screwing isnt required as the nails wouldnt crack vinyl. Yes it could perhaps possibly make a dent in the flooring it it became loos. (i have never hear of this) and it is much faster. Vinyl is not (as we all know) the same as ceramic or stone tile. Also when work with a very thgin ply screwing may not alwys be best as the head can at time be close to counter sinking through the ply and with high traffic could potentialy go straight though thin ply. It is not as common for thick ply to be used for this type of floor unless part of the floor need to be raised to meet a higher part (the joining of two rooms for example)

[tfs]

I appoligise in for my bad spelling and grammer etc

I just think and try to keep up when im typing

[doug boardley]

screwing the ply has nothing to do with cracking tiles etc, it's to keep the ply securely anchored to joists/floorboards!! any deflection movement etc will eventually work ring shanks/nails loose.

[FreeD]

thanks tfs...with vinyl floor doesn't need to be level does it...just flat?

[tfs]

screwing the ply has nothing to do with cracking tiles etc, it's to keep the ply securely anchored to joists/floorboards!! any deflection movement etc will eventually work ring shanks/nails loose.

yes ofcourse they will but its not as much of an issue with this type of flooring.

Screwing is obviously used as its achieves a better grip but nails will crack tiles if they become loose so that is in fact a reason for not using them

[tfs]

thanks tfs...with vinyl floor doesn't need to be level does it...just flat?

doesnt need to be level mate unless this is has been requested ofcourse.

Important to be flat to look its best to get a long life from the flooring

[FreeD]

guess its good practice to level the floor anyway before laying any type of flooring..

[doug boardley]

yes ofcourse they will but its not as much of an issue with this type of flooring.

Screwing is obviously used as its achieves a better grip but nails will crack tiles if they become loose so that is in fact a reason for not using them

why is that then?

[tfs]

guess its good practice to level the floor anyway before laying any type of flooring..

yes I agree mate. You will have tolerances especialy in different areas of the home

[tfs]

why is that then?

vinyl flooring will not crack, shatter and break if a nail becomes loose.

[tfs]

I must point out Doug, I too would always screw ply to wooden floor etc as far as tiling is concerned. This is not a tiling issue and the methods are not the same.

[doug boardley]

what if the sub floor comes loose?

[tfs]

what if the sub floor comes loose?

I havent seen this happen mate or heard of it. You do get issues with flooring as you do with any trade. Even if this was the case it would be very unlikley that it would become loose to that extent, it would need to have been very poorly done in the first place.