Flooring, Cabling & Pipework

Something that has been concerning me is that the builder's intention after the roof is complete, is to start to lay some flooring. While this is not a concern in itself (in fact it is very welcome to have a floor in one's rooms), I have been wondering how I am going to deal with the pipework required to feed new radiators, and the proposed en-suite bathroom.

Traditionally plumbing is done in copper pipe, and where it has to traverse a room, notches are made in the joists under one or more of the floorboards, and the notches used to house the pipes. Cabling for electrical fittings is not a problem as the building regulations actually insist that cables are carried in holes drilled mid-way down a joist (out of nails reach) and can hence be done from below in the absence of a ceiling. Using this method would be a little more difficult when trying to fit rigid copper piping, especially as it will be difficult to drill a horizontal hole when my drill is too long for the gaps between the joists. I did, however, speak to a colleague at work, and he said that he had just managed to do it this way during the refurbishment of his bathroom, though it wasn't easy and only really worked with 15mm pipe - 22mm simply does not have enough flex in it.

I sought advice from one of the builders, as I don't want to have to cut through the T&G of a newly laid floor in order to do notches, but neither am I in a position to start laying pipework before they are ready to do the flooring. His advice was to do the work from below, and to use flexible plastic piping instead of copper. Apparently you can get fittings that allow you to interchange with copper, thus allowing connection with the existing system, and copper pipes to be used in the visible parts of the system. This is not something I have come across before, so I will have to do some research. Have any of my readers used it ? Comments ?

I have fitted two complete central heating systems before, and done some major modifications to a 3rd. However, none more recently that 10 years ago, and I guess things have moved on a little.

Coming back to my conversation with the builder, he also said that it would be unwise to lift any of the floorboards soon after they are laid. They use "joist clamps" when fitting the boards, to compress them all right up against each other. This helps prevent warping, and means that the natural shrinkage of the wood over time, will not result in large gaps between the boards. It also means, however, that if you remove a board, you will never get it to fit back in again !

You plane it to fit, it shrinks, you have a gap !