Water in foundations

[Penny]

We are almost at the end of a new build but on inspection recently discovered about 18ins of water under the house within the foundations.

Soil is clay (near Marmande). Any thoughts as to if it will be permanent problem or a result of slipshot builders combined with a very wet 12 months and therefore temporary once pumped out.

[NickP]

First call should be to the Architect or the site manager depending on the hierarchy situation. If you don't have either, take photos etc. inform builder ask for his input; if thats negative, pump out the water and keep an eye on the conditions that follow. Does the house have a cellar? if it does and the water returns after pumping it out then you should consider the possibility of tanking and land drains. But thats the worst case scenario, fingers crossed that it's excess rain water.

[Penny]

Thank you.

Site manager has been informed. Next door new house has same problem it seems (it only has the ground floor in) but will keep fingers well and truly crossed!

[BIG MAC]

Insufficient information to give a detailed replay however it sounds as though you are saying there is water being held in a sub floor void / Solum?

You may want to consider what damp proof  membranes / courses you have present and whether the water is simply from  the build rather than being replenished.

If a suspended floor / block and beam etc I would suggest that you could consider installing sub floor ventilation to allow air pressure differential to carry water vapour away. Cross ventilation via proprietary vents or air bricks in other words.

I would also install a vapour barrier in the make up of the suspended floor unless it is timber in which case I think you may have problems.