Re: Moving a rising main that's under a suspended concrete floor

We are hoping to build a summer room or a conservatory and would
>prefer it to be off the kitchen. Ideal scenario for access to this >would be to take out the kitchen window and chop out the wall below. > >Moving the kitchen base units and even the sink is no big deal >but...as usual the rising main "rises" under the sink. I only need to >move the pipe say 18 inches to one side of the window opening. > >Problem is, all ground floor rooms in our house have suspended >concrete floors, so the question is... > >Is it safe to drill a hole in the floor large enough to get an arm >through so as to grab the rising main so that I can re-route the >offending pipe? > >Has anyone tried this before? I'm not sure how deep the cavity is >below the floor so I've already realised I would need to tie some >string round the end of the pipe before pulling it below the floor (in >case I drop it). > >cheers >Mitch

I don't know how many types of suspended concrete floor construction there are, so I find it a bit difficult to clearly envisage your situation. I'm only answering your post because no-one else has yet. I take it that there's no under floor access, otherwise you'd be using it.

There's a lot to recommend the method of tying the pipe to a flexible cable but I wouldn't tie it around the pipe but find some way of fixing an eye to the end of the pipe. This way you can minimise the diameter of the new hole you make and fish for the cable instead of making a hole big enough to put your arm through, which if badly placed could damage an important part of the structure of the floor.

Tony,

Thanks for the reply, yes we have no underfloor access, I should of course have pointed out that the rising main is under the window that we intend to chop out to make an entrance to the proposed extension.

I'm going to try and contact the builders to ascertain the nature of the suspended floor. Some of them I think use concrete beams that are infilled with blocks. In that case I shouldn't need to worry about the hole, as long as I drill through a block and not a beam :o)

My initial thought was that the floor itself was made from pre-stressed slabs, a bit like lintels. Drilling a wide hole in one of those would presumably relieve the "stress" and thus allow the whole "lintel" to fold.

I'll let you know what I find out from the builders.

cheers Mitch