Have recently had a loft extension done (by a reputable company) and have noticed that we now have several bulging lines running across the ceiling in one of the bedrooms below. The other bedroom doesn't have any bulges but quite a few cracks. When I say bulge I just mean a slight roundness rather than anything really huge. But it's certainly noticeable.

Our property is edwardian and has the traditional lathe and plaster ceiling. I believe that having floorboards put down above can weaken such a structure and am keen to receive any advice from anyone who has experienced a similar problem. I have spoken to my builder and he's going to come and have a look but I want to be armed with information/advice so that I can ensure that I get the right response from him.

Thanks
marilyn2911

It could be that the floor joists were not 'up to date' enough and had settled,upon which the new floorboards made them compress and cause the ceiling to crack and dip.. but this is total speculation..

Perhaps some pictures how it is now?And then with what he says we can take it from there?

One more thing, were there any floorboards in this loft before?What exactly did they do for this extension?

I believe there were boards down up there already. Re photos - have taken some but it's hard to see properly. I guess the logical thing to do is wait and see what the builder say. But thanks anyway.