# Floorboards on a concreate floor - what am I doing this for?



## Graeme (12 Dec 2009)

I am sure this has come up before, so apologies if I am covering old ground.

I have a 'friend' who wants me to put a softwood floor down in his shop/gallery. (I should say no and run like hell, but he is a nice guy and the alternative chap has had issues!). The floor (5M x 15M) is good solid concrete which he tells me already had a damp proof membrane beneath it.

I was thinking of options and am leaning toward battening the floor then laying the boards directly on top.

Do I need a damp proof membrane below the batten?
What is the minimum batten thickness you think I can get away with (finished height may be an issue)?
The floorboards are 20mm T&G, what sort of spacing do you think?

I was thinking frame fix the battening to the concrete. The nail gun the floor boards to the batten. Simples!

But I thought you guys would tell me what a stupid idea it is!  

Cheers
Graeme


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## 9fingers (12 Dec 2009)

Firstly check the damproof course theory. Lay some sheets of newspaper on part of the floor and then some polythene on top.
After few days check the newspaper is dry.

If all is well I can't see why you should not batten as you suggest.

I have a floor like this in my house and it has been fine for the last 25 years

You might want to put some insulation between the battens and if so laying some polythene on the warm side of the insulation would be a sensible precaution against possible condensation before laying the boards.

Space the battens on 400mm centre for a good bounce free floor.

If the concrete substrate is not completely flat & level, then you might need to fit shims under the battens.

hth

Bob


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## Digit (12 Dec 2009)

Nothing wrong with Bob's newspapers but I use a piece of glass and seal it to the concrete with plasticine.

Roy.


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## 9fingers (12 Dec 2009)

You're just posh Roy :lol: :lol: 

Bob


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## Digit (12 Dec 2009)

:lol: :lol: :lol: 

Roy.


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## misterfish (13 Dec 2009)

In my workshop the concrete slab seemed dry and showed no sign of damp with polythene taped to the surface for a few days. Despite this I still covered the slab with a proper dpm poly sheet, then used pressure treated 3x2 battens to support the floor. being a belt and braces person I also put a layer of building DPM (the sort used in brick walls) under the battens. I then filled all the spaces between the battens with rockwool and finally covered it with MR flooring chipboard. This has worked fine and the floor is a comfortable surface to work on. I did all this as the workshop in the previous house was an old dairy with plain concrete floors which I found uncomfortable to work on for protracted periods and also very cold in winter.

Misterfish


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## Graeme (13 Dec 2009)

Brill. Thanks for the advise. I will check the dampness or otherwise of the concrete floor.

Any thoughts on minimum thickness of battening I can get away with?

Cheers
Graeme


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## OldWood (13 Dec 2009)

I appreciate I'm going off topic slightly, but there will be people reading this thread thinking about concrete floor comfort.

I'll put in a plug for the interlocking square rubbery flooring you get from Costco - at least that's where I get it from and it must be available elsewhere. Comfortable, hardwearing, easy to fit, tool protecting, easy to lift for cleaning under - and around £10 for a pack of 6 (or is it 8!??). Also makes a good tent floor if you are static camping.

OW


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## 9fingers (13 Dec 2009)

Graeme":29ko47g5 said:


> Brill. Thanks for the advise. I will check the dampness or otherwise of the concrete floor.
> 
> Any thoughts on minimum thickness of battening I can get away with?
> 
> ...



I think you are laying the battens directly on the concrete (?) Then the wood is in compression with all the load transferred to the concrete. All the battens have to do is be deep enough to take the screws/nails holding the boards down and resist splitting. So possibly an inch minimum?
The insulation thickness is another consideration and you need to ensure that it is not compressed below its nominal depth.


Bob


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## Graeme (13 Dec 2009)

Cheers Bob, thats what I thought. Its great to be able to bounce ideas of others!


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## laird (13 Dec 2009)

Never having laid a wooden floor ontop of concrete (but having laid T&G, hardwood, and veneer floors) this is a question, not a suggestion.
If space is tight (and the concrete is level, or can be levelled) can you not just put a DPM down and then lay a floating floor directly ontop of that ? (or possibly put a layer of the thin polystyrene- like damper between the DPM and the wood floor?).


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## Digit (13 Dec 2009)

In my (limited) experience, unless the battens are secured to the concrete the floor will 'bounce.'

Roy.


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## mack9110000 (13 Dec 2009)

If height will be an issue why not use Elastilon or the Screwfix clone,this would take care of any problems with moisture or bounce.
mack


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## laird (13 Dec 2009)

Digit":2ui6zhy7 said:


> In my (limited) experience, unless the battens are secured to the concrete the floor will 'bounce.'
> 
> Roy.


The "polystyrene" type roll prevents this (I must find out it's proper title). So no


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## misterfish (14 Dec 2009)

Digit":381esaz4 said:


> In my (limited) experience, unless the battens are secured to the concrete the floor will 'bounce.'
> 
> Roy.



I forgot this step in my previous reply- I did this with my 3x2 battens and used hammer in frame fixings where the plastic 'rawlplug' goes through the wood and into the concrete. I also wanted the 3 inch depth to give a reasonable depth for insulation.

Misterfish


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## RogerS (14 Dec 2009)

mack9110000":1mr6m5p0 said:


> If height will be an issue why not use Elastilon or the Screwfix clone,this would take care of any problems with moisture or bounce.
> mack



Oh no it doesn't. Floors still bounce with this stuff plus it can be a nightmare to use.


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## mack9110000 (14 Dec 2009)

Digit":1k24g1ym said:


> In my (limited) experience, unless the battens are secured to the concrete the floor will 'bounce.'
> 
> Roy.


Floating battens are not uncommon,but they have foam attached to one side,Durabella accoustic systems are one of the more prominent leaders in this field.
As I have said before any competent DIYer can use Elastilon,and if the floor still bounces there must be a problem with the subfloor.
mack


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