Sub-floor question

**crumble** · 31-05-2011

Hello all,

First of all, I'm not a tiler but I have a few questions relating to flooring so I hope you don't mind me asking here. If you know of a better place for my question to be asked please do let me know.

So... the ground floor of my house has what I believe to be an ashphalt sub-floor and appears to be about 12mm thick. In the kitchen on top of the ashphalt are vinyl floor tiles, stuck directly on.
The ashphalt in the kitchen has begun to break up and crack, and has cracked the vinyl tiles with it. It’s only happening in the kitchen. The house was built in 1988 and had one lady owner until I bought it a couple of years ago. I’ve noticed this happening gradually since I moved in (I didn’t see it when buying at there was lino down) I would guess that the tiles are the original flooring, however I don’t know for sure.

Has anyone any ideas why this might be happening? Any ideas would be welcome.

What would be the best thing to do, remove and replace with what is there now or is there a better method available?

I know little about flooring other than that the ashphalt acts as a damp proof membrane... and that there’s concrete below it. I wouldn’t be doing any of the repair work btw...

Again any help would be appreciated.

Thanks all

**charlie1** · 31-05-2011

Hi Crumble,

I think you should be seeking the advice of a structural engineer my friend!

**crumble** · 31-05-2011

Hi charlie,

Thanks, I see your point. Would anything structural be isolated to one ground floor room?
I've seen no problems with the sub-floor in all the other ground floor rooms (which I could see when moving in after the carpet was removed).

**charlie1** · 31-05-2011

Really no idea! i dont suppose its beyond the realms of possibility for the crack to be isolated but dont know. Have you noticed if any of your doors are becoming hard to close? are there any external cracks you can see? I would get a proffesional on this mate, we are only tilers here but some of the guys know quite a lot more than me so you might get some more advice later on

**Dave** · 31-05-2011

Hi and welcome.. it could purely be down to being to thin and stress from the subfloor has made it crack and break up.. if a tap ( sound) test and see how hollow it is over the floor area and progress to other areas to the hollowness stops..

It will more than likely need to come up and redone or another subfloor put down... also check around the edges beneath the asphalt against the external/internal walls and look for a DPM membrane..

**crumble** · 01-06-2011

Hi Dave, Thanks for replying. I did do a tap test and it does sound hollow in parts (where it's cracked) but in other areas it's very solid. As far as I can see none has cracked or come away from around the walls, so I'd need to check once it's all taken up.

Is asphalt still used in this way or is their a more recommended product now?

Thanks again, really appreciate your help.