nikki

Ah ok! That makes much more sense! Thank you!

2 layers of insulation in some areas might work I guess. I’m just trying to get my head around how that would work i.e. cutting a slope into the first layer or something. Unfortunately the current floor level is unlevel across the entire slab (90sqm) and not just corners or pockets so that makes it harder to fix I think. Difference of 8cm in the worst part.

Yes all the way up to the current floor level. The difference is approx 8cm in the worst part. It’s a gradual slope across the entire slab so unfortunately it’s not just corners or pockets to be corrected. 2 layers of insulation in some areas might work I guess. I’m just trying to get my head around how that would work i.e. cutting a slope into the first layer or something.

No, not Scotland. We’re in Mid West Wales. The floor level is off through out the entire extension (approx 90sqm). The difference in floor level is about 8cm in the worst part. It’s a gradual slope from one corner to another so it’s not just pockets of it that are unlevel - it’s the entire slab. FFL will be approx 15cm higher than current FL but obviously will be quite a bit higher than this in the lowest corners. I don’t have the u-value we need to achieve at the moment. The plans were submitted by the previous owner and never passed on to us when we bought the house. Waiting for building control to send them to us so we know the u-values needed for all aspects of the build (not just this). Our builder said 80mm celotex will be ok though.

Both. Seems the original builder used a tape measure instead of a level when doing the walls as the walls followed the slope of the foundations. Our builder has fixed the walls now (we have roof on and windows in now) and they checked plum/square and the walls are all fine now. Just the foundation that’s still unlevel. We wanted to do the insulation on the floor ourselves though to save some money so need to figure out what the best approach is to handle the unlevel foundation issue 🙂

Thanks! I’ll check and report back. I think it might have been around 90mm though 🙃

Hi. We bought a house with a large extension that had already been started which included the foundation and some of the blockwork. It was all signed off by building control before we bought it (according to the building control officer). Unfortunately, upon starting work to finish it our builder found that the foundation is not level (as was the blockwork 🤦🏼‍♀️) despite building control signing off on it all. My question now is: when we level the floor, should we do this with the screed layer on top of the insulation (so the screed will be thicker in some rooms) or should we level it out before we lay the insulation down so the screed on top will be an equal thickness across the whole extension. Or another options I haven’t thought of? The extension is approx 90m2 so it’s a fairly big area.

Hi everyone. I'm trying to put together a budget for a self build so we can work out if our dream of building our own house can become a reality! I was wondering if anyone knows how much groundworks would cost for a footprint of approx 1200sqft (110sqm)? I know it depends on a lot of things and you don't really know until you have bought the land, but I just wanted to get a broad range of what to expect for the groundworks side of things, and how much we should budget for it realistically. We would be building in Scotland (probably the Highlands) if that helps. Thanks!