Thick PVC/DPM Sheeting in sub-floor? Good or Bad idea...

[dishman]

I am going to be doing a bit of diy in the void/sub-floor under the house. There is a a decent 70cm headroom, but with it being a 1930s property the floor of the void is silty earth. It seems pretty dryish, just a hint of dampness as one would expect. But it does get all over the overalls.

As I am going to be climbing in and out quite a lot I thought I might make the whole process a bit cleaner by putting some thick black plastic sheeting down. There is lots of thick dpm sheeting available.

Is there any particular reason (that I am not aware of) why this should not be done. The void is well ventilated with air bricks, it seems pretty dry down there. I just wondered if a large surface area of sheeting could have unintended side effects.

I am just going to line the floor, weigh it down at the edges and make a nice smooth clean (well...cleaner) crawl space. Nothing more....

Many thanks in advance

 

[John D v2.0]

I think as long as the sheet is weighted down you'll be OK. Just you don't want it too be floating on top of a lake or anything.
I think the modern requirement is a layer of concrete, but you can make your own mind up by how wet the ground is.

 

[dishman]

Thanks

Yeh - it seems pretty dry, but with just enough moisture content to be a tiny bit tacky. I crawled down there yesterday and got all over my clothes, but brushed off pretty easily.

Just wondering if a large piece of plastic sheeting would/could encourage condensation to form, (like putting a plastic sheet on a washing line). But I guess with good ventilation it should not be an issue.

Just thinking of a way to make it a cleaner experience.....

 

[dishman]

Out of interest, with modern voids having a concrete base, what happens in the situation where water gets in? I assume it will just flood?

 

[John D v2.0]

supposed to fall to a drain or be higher than the outside ground level

 

[dishman]

Hmm, in that case, maybe I am better putting some water permeable membrane down. Similar to that weed matting. I do not like the idea of butting something down that will just allow water to pool if it gets in.