laying reclaimed floorboards on to screed

[stillfirm]

Hi, I am looking at flooring a 20 year old ground floor extension with reclaimed floorboards (timber tbc as I am literally at investigation stage). the floor is concrete screed and will be finished level.

I am thinking a base layer of thermal underlay, but then not sure on fixing the boards them selves. I am aware of leaving an expansion gap around the edges of the room which the skirting will cover.

I would really welcome the forum's wealth of knowledge on this subject!

 

[Lons]

The first thing to ensure is that if new screed or levelling compound it must be allowed to dry fully before putting down boards. New concrete can take at least a month and sometimes more. It must also have a reliable DPM.
That said, you could stick the boards to the floor with a proprietory flooring adhesive or lay it as a floating floor over an underlay like laminate or use one of the foam base underlay which has an adhesive to one side (laid uppermost), which holds the boards together but allows expansion movement. I've used this method a number of times over the years for oak T&G and it works very well. http://www.screwfix.com/p/self-adhesive ... id=1398106

Bob

 

[andersonec]

The damp proof barrier and thermal insulation should be under the screed then battens are screwed to the screed and boards fixed to them, you could also put polystyrene between the battens to deaden the sound.

Andy

 

[Noel]

The damp proof barrier and thermal insulation should be under the screed then battens are screwed to the screed and boards fixed to them, you could also put polystyrene between the battens to deaden the sound.

Andy

Exactly, as Andy has said. Screwed batons will also give the floor some "life". Also with batons you can blind nail on the tongue or use cut nails through the surface which will give the floor character. And lay them randomly rather than picking and choosing each board.
With this method you will not have too much problem if you need to lift them due to leaking pipes, damage etc.

 

[Lons]

The damp proof barrier and thermal insulation should be under the screed then battens are screwed to the screed and boards fixed to them, you could also put polystyrene between the battens to deaden the sound.

Andy

Exactly, as Andy has said. Screwed batons will also give the floor some "life". Also with batons you can blind nail on the tongue or use cut nails through the surface which will give the floor character. And lay them randomly rather than picking and choosing each board.
With this method you will not have too much problem if you need to lift them due to leaking pipes, damage etc.

Definately the best scenario method but what I've found in every single case is that the increase in floor height would produce a step up into the room/s which has been unacceptable to my customers and therefore not possible.

Great if building an extension from scratch or say a whole ground floor for instance, but not when you need a reasonably level transition from other existing surfaces such as carpet.

Bob

 

[stillfirm]

thanks for your thoughts guys - i had contemplated the the batoning, but given i am running boards from the front door through to the back of the house through the kitchen, there would be step downs in to the lounge + dining rooms (carpet), and would also cause me problems with the planned install of level threshold bifold doors.

i am liking the idea of thermal underlay strips, with a sticky topto hold the boards - do you think it would be an issue to use non t&g with this method?

 

[stillfirm]

also just looking online for other wood floor adhesives - can this stuff be applied to foam underlays or should it just go straight on to the concrete/levelling compound?

 

[Lons]

also just looking online for other wood floor adhesives - can this stuff be applied to foam underlays or should it just go straight on to the concrete/levelling compound?

If using std adhesive it needs to stick the boards direct to the floor.

It is possible to use square edge boards but I wouldn't personally and if you can't get / make T&G, another method is a loose tongue (groove all edges say 6 mm and rip up some 6mm ply for the tongues.)

Adhesive foam works well but there is an art to using it. You should find video around on the net if you look but basically I lay out some of the underlay plastic cover side up, peel back just enough of the film to stick down the first row of boards, feed in the next row slowly pulling back the film as you go.
I use the strap clamps for laminate flooring to pull the joints tight first as you don't get a second chance. The adhesive sticks like s*** to a blanket

Easier than it sounds but have to do it right or you'll spend hours lifting it and scraping off the back of the boards :wink:

I'm happy to post you a small scrap bit to play with if you pm me your address. I keep all the offcuts as it's excellent for lining drawers and toolboxes in the workshop as well as under the bases of ornaments, carvings and turnings.

Bob

 

[Meader 1]

If using std adhesive it needs to stick the boards direct to the floor.

It is possible to use square edge boards but I wouldn't personally and if you can't get / make T&G, another method is a loose tongue (groove all edges say 6 mm and rip up some 6mm ply for the tongues.)

Adhesive foam works well but there is an art to using it. You should find video around on the net if you look but basically I lay out some of the underlay plastic cover side up, peel back just enough of the film to stick down the first row of boards, feed in the next row slowly pulling back the film as you go.
I use the strap clamps for laminate flooring to pull the joints tight first as you don't get a second chance. The adhesive sticks like s*** to a blanket

Easier than it sounds but have to do it right or you'll spend hours lifting it and scraping off the back of the boards

I'm happy to post you a small scrap bit to play with if you pm me your address. I keep all the offcuts as it's excellent for lining drawers and toolboxes in the workshop as well as under the bases of ornaments, carvings and turnings.

Bob

Hi, I am looking to fix Reclaimed floor boards which I think are pine onto a flood concreted screed which is very level but has wet underfloor heating within. I did think of the idea of fixing battens should I not be able glue them directly onto the screed. Is there a glue I can use as I will not be able to use screws due to the underfloor heating. So my idea is - glue the battens (If unable to glue them directly onto screed) then screw the reclaimed floor boards to the battens? Do you think this will work?

 

[Housey210]

"will be finished level" are you laying the screed? Onto what, oversite or insulation? what thickness? Done a similar job on council houses years ago, there the spec was bevelled timber at 400ctrs packed and levelled through out, into the voids the screed. Week later we laid the floorboards.

 

[Sachakins]

If your screed is perfectly flat and even, and I've yet to gind one that is, then gluing batons will be ok. But the barons must be level, any undulations must be shimmed out, that's were glueing down becomes an issue, as and gaps and the glue won't adhere, and the only way to avoid its is to scribe each baton onto floor.
But as you have said its perfectly level (), then I don't see a problem.

If there are undulations, you could consider a layer of self leveling cement first.

 

[Sachakins]

Another thought would be to board out the entire floor in 18mm ply, then work your flooring on top.

The ply would be heavy enough to lay flat without needing to secure it to the screed

 

[Jacob]

Hi, I am looking to fix Reclaimed floor boards which I think are pine onto a flood concreted screed which is very level but has wet underfloor heating within. I did think of the idea of fixing battens should I not be able glue them directly onto the screed. Is there a glue I can use as I will not be able to use screws due to the underfloor heating. So my idea is - glue the battens (If unable to glue them directly onto screed) then screw the reclaimed floor boards to the battens? Do you think this will work?

No need to glue the battens the boards would keep them in place. n.b. nails much neater than screws.

 

[Meader 1]

No need to glue the battens the boards would keep them in place. n.b. nails much neater than screws.

Thank you Jacob, I assume you mead once nailed to the batten the weight of the timber should hold it all down and in place? Are able to help with what centres I should set the battens at and also what type of nails. Thanks Steve

 

[Jacob]

Thank you Jacob, I assume you mead once nailed to the batten the weight of the timber should hold it all down and in place? Are able to help with what centres I should set the battens at and also what type of nails. Thanks Steve

You'd have to decide where you want your finished floor level e.g. where it meets the next room when you open a door etc. It could be that battens take it too high - back to vinyl!
If no prob maybe 50mm square battens which would take 60mm lost head nails? At 500 to 600mm centres depending on board thickness

 

[Meader 1]

You'd have to decide where you want your finished floor level e.g. where it meets the next room when you open a door etc. It could be that battens take it too high - back to vinyl!
If no prob maybe 50mm square battens which would take 60mm lost head nails? At 500 to 600mm centres depending on board thickness

Hi, Thanks for this. I think 50mm timber will be too much so perhaps 20mm battens may work. It will mean that there will be a difference from the lounge/Kitchen to the Bathroom where we will be laying tiles. This will have to be made up so there will be no lip/step. We are lucky in as much it is an annex we are converting with high ceilings from outbuildings so at a fairly easy stage. so to up the levels but perhaps not 50mm timbers will work. Your response and help are apreiciated. Steve

 

[JimTaylor]

We put a two part finish on the floor when we laid 18mm oak t&g. This is a damp proof and allows wood to be laid onto green concrete. It also gives a key for the glue as the surface af the scree is too powdery for the glue to adhere to.
Depending on the age of the floor you may need 2 coats. We followed the instructions to the letter and only needed one coat. It drys very shiny like an epoxy finish with a light green hue, there was only a 25 minute working time for the finish by 26 minutes it was going off. From memory it was made by Sika. We then laid a foam rubber neoprene underlay with slots cut into it at even spacing. We then laid beads of glue in the slots to glue the boards down. The glue was also by Sika. You cut the nozzle to form a triangular bead of glue to lay the boards on. I was able to lay 4 runs of board at a time, then more beads of glue. When we moved house the flooring had been down about 10 years and we never had any problems. The hallway went from concrete to wood and the glue worked on both surfaces.
We took the skirting off prior to laying the floor as I didn’t want to use a scosha trim ( don’t think I spelled that correctly).

 

[Jones]

Underfloor heating won't work well with too much insulating wood on top and the timber won't like it much either, with reclaimed stuff you could get a lot of movement troubles. An engineered timber floor designed to go over underfloor heating and glued or loose laid as per instructions would be the best and literally guaranteed way to go.

 

[Sachakins]

How thick are the reclaimed boards, that'll determine your batton spacing.
16" centres is normal, 24" centres liable to allow sag in boards when walked on.
I would not go over 16" centres personally, probably drop down to 12" centres if your boards are not T&G, as its the T&G thar prevents sag or deflection when walked on, more than the thickness of board.

So without T&G, then square edge boards need to be thicker and you need far more and closer batons than with T&G boards

 

[Meader 1]

How thick are the reclaimed boards, that'll determine your batton spacing.
16" centres is normal, 24" centres liable to allow sag in boards when walked on.
I would not go over 16" centres personally, probably drop down to 12" centres if your boards are not T&G, as its the T&G thar prevents sag or deflection when walked on, more than the thickness of board.

So without T&G, then square edge boards need to be thicker and you need far more and closer batons than with T&G boards

Hi, The boards are 20mm thick so would 400mm centres be fine for these? What type of screws would you use as we don't want ugly screw heads but we want them to be secured without too much movement? I was suggesting 40mm screws as the boards are 20mm and the battens we are fixing too are 25mm. What are your thoughts please.