# Tiles over floor with no vapour barrier?



## willywonker (Oct 27, 2016)

Hi,

I have new build garage, completed just over a year ago when the house was built. Has the standard new build never ending dusty floor on which I plan to lay some Duramat pvc tiles.

The house builders tell me there is vapour barrier in the slab, but I'm not convinced as where I had left a couple of bottles of oil when I lifted the bottles after a few months the slab was wet underneath. 

So my concern is that if I do lay the tiles I will get moisture sitting underneath the tiles, trapped between them and the floor. Which I'm worried will either make the garage damper (not good!) or possibly damage the slab by being wet all the time.

Hoping someone might have some experience or knowledge on this, and let me know if worrying over nothing!

Cheers


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## Jack R (Dec 15, 2014)

When was the garage built? Concrete will take a month per inch of thickness to cure fully. Chances are that there is a vapour barrier as most new homes seem to have it nowadays, however it's also likely that it won't have any insulation under there so it could be condensation caused by the difference in temperature between the oil and concrete.


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## rf860 (Jul 24, 2011)

Would be very surprised if there was no vapour barrier (damp proof membrane). If there's not you'd have a case for them to break out the floor and relay with damp proof membrane installed. 


Sent from my iPhone using Tapatalk


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## willywonker (Oct 27, 2016)

JR1982 said:


> When was the garage built? Concrete will take a month per inch of thickness to cure fully. Chances are that there is a vapour barrier as most new homes seem to have it nowadays, however it's also likely that it won't have any insulation under there so it could be condensation caused by the difference in temperature between the oil and concrete.


Garage was built approx Jan ish 2016.



rf860 said:


> Would be very surprised if there was no vapour barrier (damp proof membrane). If there's not you'd have a case for them to break out the floor and relay with damp proof membrane installed.


The builders say there is membrane in there, but honestly I have little faith in what they say anymore! The NHBC have no requirements for there to be one, so no guarantees!

Is there a way to tell?

And if there's isn't one, is it likely to be an issue to lay the tiles?


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## Jack R (Dec 15, 2014)

You can sometimes see it around the edges but you'll have to look closely, possibly use something to scrap along the edge to take the cream off so to speak. It's not the the end as you could just seal the concrete with a waterproofer, then you'll be able to lay a new floor on top.


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## wlmoate (Nov 29, 2014)

Hi,

You could core a small hole to inspect for a DPC. Then patch a repair. If you haven't got a core bit, stitch drill a small square and chisel out and then repair the inspection hole. You can buy pre-mixed concrete (dry) from B&Q.

If there isn't one it isn't the end of the world as you could use a tanking solution before tiling http://www.ultimatehandyman.co.uk/how-to/diy/floor-tanking

Wayne


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## Guest (May 18, 2017)

Id agree with...
"You can sometimes see it around the edges but you'll have to look closely, possibly use something to scrap along the edge to take the cream off so to speak. It's not the the end as you could just seal the concrete with a waterproofer, then you'll be able to lay a new floor on top."

If its a detached garage,I would not expect there to be a DPM.If the garage walls are connected to the house...there maybe.But..as the garage slab has to be lower than the house slab,its not a definate...the DPC,s are not at the same height.
To be fair..the NHBC do make the standards they work to,available to everyone.So everyone knows what their getting for their money...The builder works to the NHBC standard

Garage Floors 10.1.4
Generally, a DPM is unnecessary, except where:
„ it is needed to prevent dampness entering the home, or „ the floor has to be protected against chemical attack from the ground


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## Jack R (Dec 15, 2014)

aka.eric said:


> Id agree with...
> "You can sometimes see it around the edges but you'll have to look closely, possibly use something to scrap along the edge to take the cream off so to speak. It's not the the end as you could just seal the concrete with a waterproofer, then you'll be able to lay a new floor on top."
> 
> If its a detached garage,I would not expect there to be a DPM.If the garage walls are connected to the house...there maybe.But..as the garage slab has to be lower than the house slab,its not a definate...the DPC,s are not at the same height.
> ...


Pretty much sums it up :thumb:


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## willywonker (Oct 27, 2016)

Thanks guys, had a quick look and poke around the edges and can't see anything. If I drill how deep is the dpm likely to be beneath the surface?

To be honest on one of the reasons I'm looking at PVC tiles is to avoid all the prep work, it's a detached double garage with too much stuff, and two cars in which it would be less than ideal to empty to allow stuff to dry on the floor, like waterproofer, etc.

I asked Duramat and they didn't seem bothered saying the tiles fit tightly together and this prevents moisture coming up through they, which is fine. But I need to understand if the moister is trapped under them does this matter? Presumably the slab will still have moister in whether its trapped at the top under the tiles, or a little further down by dpm?

Maybe I am overthinking this!!


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## willywonker (Oct 27, 2016)

aka.eric said:


> To be fair..the NHBC do make the standards they work to,available to everyone.So everyone knows what their getting for their money...The builder works to the NHBC standard
> 
> Garage Floors 10.1.4
> Generally, a DPM is unnecessary, except where:
> „ it is needed to prevent dampness entering the home, or „ the floor has to be protected against chemical attack from the ground


The thing is some builders go beyond NHBC, our last new build had a really well built garage, double skinned walls, the lot. And I must admit I (stupidly) never really gave it that much thought until we moved in to find a warning sign on the garage wall that says in inclement weather the walls and floor may become damp and you should avoid storing items of value against them....! Which obviously makes it the perfect place to store an old italian car that's prone to rusting.....


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## Jack R (Dec 15, 2014)

Might be worth investing in a poly tunnel before it dissolves


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## RedUntilDead (Feb 10, 2009)

I have a double detached garage and ours is over 15 years old now. I laid interlocking pvc tiles over the dusty concrete surface about 3 years ago. I think it makes the under surface sweat. Water seeps down but damp doesn't come through. Good ventilation is key but things still rust. When I put the car away after it's been out in the rain the water has to go somewhere if your with me.
Not an issue.


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## Sean_Jaymo (May 24, 2006)

Ours is a Taylor Wimpey garage and that has a dpm. Who built the garage?


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