Wood You Like Ltd
natural wooden flooring (Kent UK)
natural wooden flooring (Kent UK)
Lately we’ve seen (DIY) forum posts, questions in our own inbox and even results by diy-ers and builders alike, about (and in the results missing): not leaving enough expansion gaps when installing wooden floors
Most know about gaps and leaving them around the perimeter of the floor – using the simple rule of thumb: 3-4mm per meter width of the room with a minimum of 10mm – but then go wrong at certain points in rooms or hallways.
You have to leave an expansion gaps ALL AROUND the perimeter of the whole floor, not just here and there or where you can cover the gap with skirting boards.
If you don’t have a sufficient wide expansion gap at one single place, like a doorpost or in front of the fireplace or staircase, all the other wide enough expansion gaps are rendered useless! You wood floor is not going to think: Oh, there’s not a gap so I won’t expand there. Believe me: it will!
A wood floor, specially a solid wood floor, will expand evenly. Most of the times that is: when it is stuck at one certain point it can’t and will raise its level at or around the point that is blocking its normal movement. For instance when glue has dripped out of the T&G and sticks the wood floor to the underlayment.
Or when you haven’t undercut your doorpost or laid the floor flush against the side of a fireplace or staircase. Reasons we heard: skirting board doesn’t reach that far; don’t know what to cover the gap with around the fire place or I don’t like to use a divider between the rooms where the wood floor is installed in two different directions anyway.
We cannot change the laws of physics – it’s as simple as that!
Leave expansion gaps all around the perimeter, there are various solutions – proper and aesthetically pleasing solutions – for all situations:
* Doorposts: undercut architraves and doorpost with handsaw as far as the height of the new floor and chisel out what is needed – making sure you chisel out enough for the floor to hide its edge and still have room to expand
* Fireplace: leave an expansion gaps around and when the floor ends lower pin down a flat solid beading on the floor – covering the gap in a neat and almost flush-way. When your floor ends higher use a so-called End-threshold to finish it off: giving you both the needed expansion gap as a neat very small ‘step’ from floor to fire-place.
* Stair: if the stair carpet isn’t thick enough to cover the gap (most professional carpet fitters will ‘double-back’ the carpet at the bottom of the stair, giving you twice the thickness of the carpet) you either install a flat beading on the floor or use mastic filler (curved stairs come to mind). In some (rare) cases you could even fill the gap with a cork strip – as long as you can reach the strip to lift it out when the floor threatens to expand!
Leave gaps everywhere – as said before: we mere mortals cannot change the laws of physics!
Some issues keep recurring: cork strips among them.
A few days ago we received the following email:
"I realise the importance of leaving an expansion gap around a wooden floor (oak parquet in my case) but can you tell me why we are told to insert cork strips around the edge? Surely the cork is only taking up valuable expansion room. Is it ok to just leave a 10mm gap all around?"
This was our (recurring) answer on this subject:
Thank you for your question. We are trying so hard do tell everyone exactly that: DON'T use cork strips to fill the expansion gap.
These were used many, many years ago to divide design parquet pattern and the block border and somehow ended up in the expansion gap.
So, you are absolutely right. Leave your expansion gap 'empty' to cater for any natural seasonal movement of your wood floor."
The reply:
Many thanks, it's nice to be right for once!
Of course he was right, we still don't understand how the old-fashion cork divider strip ended up as recommendation to fill your expansion gaps.
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Comments (33)
I thought that the cork strips were to fill the gaps so that the floor couldn't move, but be flexible enough to allow the floor to expand and contract with temperature/moisture/etc. I thought that without the cork strips the floor may move to fill the gap at one side, leaving a larger gap at the other side, whcih might not be covered by the skirting, or whatever you use to cover it.
Happy to be told this is wrong, but would welcome explanation as to how to stop the floor migrating towards one side.
Hi Robin
Originally, used between pattern and (block) border of design parquet, that is indeed where it was used for.
Mainly because design parquet, due to the many individual blocks would hardly expand/shrink and so the cork would work.
For some unknown reason these old-fashion 'cork-strips' keep being suggested to fill the expansion gap when installing modern floorboards, where the expansion gap is at the perimeter of the whole floor - not in between pattern and border. And this is where things go wrong. Cork can handle the small movements of design parquet, it CANNOT handle the sometimes large movement of solid floorboards.
As for floor movement: the weight of the wood floor itself in combination with the weight of any furniture will make it stay put. And yes, there will be seasonal movement, but if you keep an eye on your home climate, air humidity and ventilation your expansion gap is capable of handling this movement. As long as you leave sufficient gaps all around the wooden floor, including where there are doorposts, fireplaces and even radiator-pipes.
Hope this helps
Wood You Like Ltd
Hi i am about to lay a solid wooden floor in a room 7 x 4 and continue though an archway to a dinning room 7 x 3 . I am in tending to screw every piece to the floor using the screws provided with the floor is this ok and does screwing every piece stop the expantion regards tony ps the planks are to be layed length ways across the living room through the archway and continue across the dinning room
Hi Tony
Although we are not in favour ourselves to screw a floor down, we know there is one brand who created special screws. If you bought this brand then it is always best to follow their installation instructions.
However, no matter which installation method you use, you have to keep expansion gaps all around the floor - in your case 15 - 16mm (if it's an Oak floor you're installing).
I'm presuming you are installing the new floor on top of existing floorboards? If so and the new boards are installed in the same direction of the existing boards, you'll have to over board first with hardboard or plywood to prevent any unlevelness of the old boards effecting the new boards and creating movement.
Hope this helps
Wood You Like Ltd
Hi there,
We just had a very stupid man (who called himself a laminate floor specialist) lay our laminate. I wanted to keep the existing skirting and avoid having to use extra stips to cover the expansion gaps. I thought he would have removed the skirting to ensure sufficient space was left between the laminate and the wall but clearly 3 weeks later when my lounge became a trampoline (where the only place the laminate could expand to was up) we realised he hadnt. Anyway we are unable to get him to come back to redo the job so we are faced with task of doing it our self..... anyway from my reading of this page and other forums I would just like to clarify a couple of points: Is expansion cork an absolute no no (can we use it on one side of the wall without having to remove the skirting and then on the other side remove the skirting and not use expansion cork?) or do we really have to remove all the skirtings and use spacers? Please help...
Hi
When you appoint a fitter, always makes sure he and you understand what is needed/required or wished for. Not all fitters will remove skirtingboards and then only when this is discussed with the client.
Cork is a definite no no in these cases, you'll have to ease the floor and then install either thicker skirtingboards or scotias/beading in front of the exiting skirtingboards
Hi, we've also just had a very stupid man install oak hardwood flooring without leaving enough expansion gaps. Sufficient gaps have now been created but some areas of the floor are still a bit bouncy due to the boards turning up slightly and I was wondering if there is a special type of screw or method to enable me to screw the floor down (into concrete) to speed up the flattening process whilst still allowing for expansion.
Many thanks
G
Hi G
If the floor has only recently been eased back then there's bound to still be some bounce while it is settling back.
Screwing the floor to speed up this process is definitely a no no! You will locally prevent the floor to expand (or shrink) normally, causing the same problem you've just corrected.
Time is the answer.
Hi,
We recently moved into a new house, and the beautiful oak floor started to lift in the hallway within a few weeks.
Having spent hours with surveyers looking for damp problems that didn't exist, your page here clearly explains what's happened, and I now see the evil cork strips all have to come out. Great advice - thanks!
One question though... My beautiful (but now wavey) floor runs across three connecting rooms, right across the house (around 12 meters with gaps all filled with cork. Doh!). I'm wondering how I can leave a gap in the doorways. Is there a solution for covering a sufficient gap in a doorway, and letting the floor move underneath it?
Thanks in advance,
Pete.
Thank you for your question - our answer will also appear on the article.
If you mean a gap straight across the doorway (from doorpost to doorpost) that would be advisable. With a plunge saw cut out a necessary gap (width of gap depending on what threshold you are going to use, a T-bar needs at least 5cm gap, a flat divider 3cm) and lift the strip of wood out.
http://www.woodyoulike.co.uk/shop/#ecwid:category=380999&mode=category&offset=0&sort=normal
Both sides of the door now have room to move and moving boards - moving during normal seasonal changes - will not effect boards in the other room.
The gaps left by lifting all cork strips out can be covered with flat beading:
http://www.woodyoulike.co.uk/shop/#ecwid:category=380999&mode=product&product=1316227
Hope this helps
Kind Regards
Wood You Like Ltd
Our oak floor was laid 3 yrs ago. This yr we had a buckling problem on one side. There was no expansion gap left. So, we are removing one side and leaving a gap, however we can't do the other side unless we rip out the entire floor. Can we jus do one side and leave a larger gap?
Hi Bridget
Normally when you cut off a small strip of the wooden floor on the one side, the whole floor will come back to its normal state. So your idea is a good one.
After this is done, just keep a close eye on the whole floor. Do you know the reason for this cupping?
Wood You Like Ltd
Hi. I'm a bout to lay oak flooring onto conctete and want going to use cork strip to fill the expansion gap (not under skirting ... I've removed them) where it will join 3 rooms with large doorways/archways that are quarry tiled. What is the issue with using cork? If I put double the gap and then fill with cork will this have enough expansion?
Hi Neal
No, sorry - increasing the width of the gap in order to fill it with cork is still asking for trouble.
In scenarios like yours, where the wooden floor "buds" up to quarry tiles we would use either flat beading to cover the empty expansion gap if the quarry tiles are higher than the floor, or we would us an End-threshold (L-profile) if the quarry tiles are lower than the wooden floor:
http://www.woodyoulike.co.uk/shop/index.php#ecwid:category=380999&mode=category&offset=0&sort=normal
Hope this helps
Wood You Like Ltd
Hi,
Had 21m2 of 22mm solid Oak floor (fully stuck) laid at home, floor was Damp proofed & latexed, expainsion around whole perimater.
Floor keeps lifting, firm have been back sevaral times, now they are telling me, the damp is coming from the walls, mind it is avery old building & I have seen their meter go into the red on all 4 walls.
Would this cause the floor to lift or is it fitter error ?
Regards
Gary
Wood will react to changes in humidity, no matter where it comes from - for instance in winter with central heating systems on, the air humidity will drop and your floor can shrink.
Not having seen the situation ourself, or if moist measurements were taken before installation took part, it is difficult to say if the damp walls are the real cause but it is possible. Did they give an idea where this moist in the wall comes from?
Hi Gary
Is it possible to check the expansion gap to see if this has closed and the floor is now pressing against the walls. The wood is clearly expanding due to the moisture coming from the walls, but if this expansion is excessive it may actually be filling the expansion gap and want to go further, hence will buckle upwards, freeing it from the adhesive.
Regards
Neal
hi can i use a gap filler on edge of my parquet flooring as i cant remove skirting and there would be a 10mm gap just thought this filler would move with the wood
Hi Alan
You could, but installing flat beading would be a neater solution (and leave the gap absolutely "free"):
http://www.woodyoulike.co.uk/shop/index.php#ecwid:category=380999&mode=product&product=1316227
Hop this helps
Hi,I am about to lay a floating 18mm x 150mm solid oak floor in the hall and kitchen and intend continue this all the way through the connecting doorway maintaining the expansion gap at the sides by removing the skirting and cutting away under door frames, this would make it a total of 7 metres, i would like to take the floor under the faciais below the kitchen cabinets by 25mm and leave it open ended so to speak ,would any problems arise in doing this. Also the washing machine is on a raised concrete slab which will make it level with the floor and i would like to seal the expansion gap,is this possible and if so what could i use.
Since there will be different climates in the different rooms, it would be better to install thresholds in the door ways, treating every room as a separate entity.
Going just underneath the kitchen units is a good idea.
If the slab is higher than the floor you could use flat beading to cover the expansion gap.
I am laying T&G oak boards in one direction in a room but in the other direction in the adjacent hall. I intend using a T-bar in the door arch between hall and room. The question is, how much gap should |I leave under hte T-bar,if any ,considering the T-bar has only 10mm
width under each side.
Hi Phil
That's a very narrow T-bar. Depending on the width of the room/floor you have to have at least 10mm gap everywhere.
Hi.Should I glue oak 18 mm t&g together. I am laying a hallway @1m x 7m.I have 6mm fibreboard underlay. And am leaving 10 mm gap all around.I would rather not glue it but would this be a problem? thanks.
Yes, you should. Or run the risk of gaps between the boards during the changing humidity over the seasons.
How long are your boards? If many short - too short lengths - it's not recommended to install a floor like this using the floating method, see here:
http://manuals.woodyoulike.co.uk/s/manualwyl/m/wylprep/l/5078-Solid-Floors-what-to-note
Hi thanks for answering my query so quickly. The boards are 600 & 500 mainly .Shortest are 300.Does this sound o.k.? Also could you recommend any glues? thanks again. Paul.
A floor like that should not be installed using the floating method I'm afraid. Too many short lengths which will make your floor very unstable and prone to movement.
You'll have to fully bond this type of floor with flexible adhesive: http://www.woodyoulike.co.uk/shop/index.php#ecwid:category=371949&mode=category&offset=0&sort=normal
Kind Regards
Wood You Like Ltd
Myabe I'm being thick, but I don't understand how to install flat beads to cover the expension gap. if you nail them to the floor, then surely when the floor expend, it will push against the wall, the same way the floor would without an expansion gap?
only difference being that instead of the floor bucking, probably the beading would snap at the point it's nailed to the floor (being more fragile).
Am I missing something?
Right in one, Sandra
Hence the recommendation to use tiny pins to fix the beading to the floor, they will simply lift out when the floor expands - and gives you an early warning system too.
Wood You Like Ltd
Karin Hermans
I have just had a solid wooden floor laid. There now appears to be gaps (just in one area) between the planks. Is this because of movement or were they laid incorrectly. The floor was a tongue and grove system that fitted together. Is there anything that I can do to correct this problem
Hi Ann
Could be various reasons.
Did your fitter/fitters use PVAC wood-glue in the T&G? If not, movement could make the boards go apart now there is nothing to hold them together.
If wood-glue has been used, has it been given enough time to bond before walking over it? This can also create gaps and then when the glue starts to harden, the boards are not together, showing gaps now.
Has the wooden floors been acclimatised before it was installed?
Is there a different heating source in that one area?
As you can read, many reasons and many questions. If you would be so kind to answer them we can advice better.
Wood You Like Ltd
Karin Hermans
Hi
I've got some solid wood acacia flooring 93mm wide, most of it is 700-800mm long and I'd like to lay it over existing boards. I know the usual rule of thumb is not to install this free floating if the boards are less than 100mm, but mine aren't far off 100mm so do you think I could install this free floating? The room size is only 2.2m by 2.75m. I assume that PVACing the T&G is still necessary?
thanks!
Hi there
This rule is there not for nothing.
http://1plus1makes3.screenstepslive.com/s/manualwyl/m/wylprep/l/5078-Solid-Floors-what-to-note
You will be taking a risk, a quick calculation comes to appr 23 - 24 rows if you install parallel the longest wall. Noting the maximum 800mm long boards you will end up with too many joints (hinges).
Sorry, but it would be better to secret nail here.
Wood You Like Ltd
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