Send in your questions to Steve. . .

Q I have recently fitted a new power shower cubicle with two bar pump in my bathroom but I cannot get the water to flow when I turn the shower on. It only flows when I flick the basin tap for just a second or flush the toilet, both of which are also on the pump. The unit has a non-return valve in its control unit and I think it may need extra pressure. I connected the mains water to the cold supply and the shower worked perfectly, which it does as soon as it has water flow (just to test it). My storage tank is about 1m above the shower head and is 8m away and has an 18mm water supply. It seems obvious I may need to raise the tank higher.

John Clifford

A The storage tank probably is too low. The best way to get the correct height of the storage tank is to remove the shower head from the sliding rail and hold it against the wall. Gradually lower the shower head and when the pump comes on put a mark on the wall where the shower head is at that particular time. Then measure from that mark up to the bottom of the storage tank in the attic. That measurement is the height that you need to have the storage tank above the shower head when it is fitted in its normal position on the riser rail. If it is not possible to rise the tank by this amount then you could change the size of the pipe from half an inch to three quarter inch pipe. This will give you a greater pressure to work the pump. Remember, that if you are going to raise the storage tank you must make sure that it is fully supported across the ceiling joists and preferably supported onto a supporting wall.

Q Some weeks ago, you gave advice on dry-lining the exterior walls of a 1970s'-built house. Your first suggestion was to use plasterboard with polystyrene insulation glued to the back of it. Is this an off-the -shelf product readily available? You then suggested two forms of a batten system (one with and one without insulated plasterboard) if there were signs of dampness. My question is, assuming dampness is not an issue, how does the insulation-backed plasterboard compare with either of the batten systems in terms of heat retention? It seems to me that battens with polystyrene sheets in between and plasterboard sheets attached has to be the superior solution, but is the difference worth the effort and cost and indeed the space taken up by it. As I am thinking about insulation I would appreciate your views.

Pat Giblin

A The insulated plasterboard is readily available off the shelf, it may not be carried by the smaller merchants but larger stores will have it in stock.

The plasterboard itself is 12.5mm (1/2") and has either 12.5mm or 25mm insulation bonded to it. Insulated plasterboard on its own would be suf"cient to conserve the heat in your room. However, as recommended by professional bodies the more insulation you have the better you would benefit by placing the insulated boards onto the drylined wall with insulation between the battens. The only downside is that you are going to lose another inch all round the room.

Q I recently purchased an apartment where the balcony doesn't drain correctly. There is a drain at the back of the balcony, but the collected rain just pools and does not flow toward the drain. Is there something I can resurface the concrete balcony with to make the water flow toward the drain ?

A If this is a new apartment then I suggest you get onto the builders and get them to fix the problem. I came across a similar problem about a year ago where a builder had put in a shower tray and the water never went down the outlet because the shower tray was not fitted level and the water was actually falling in the complete opposite direction! If you end up undertaking the repair yourself I would suggest that you use a floor levelling compound. I myself would use floor tile adhesive but mixed to a thick creamy paste consistency (similar to custard) as the make up of tile adhesive has what I would term "body" as opposed to the actual levelling compound. You need this "body" as you are going to have to build up layers of the compound to get the water to flow towards the outlet. Another solution would be to lay tiles on your balcony and make the tiles flow towards the drain hole. Make sure the tiler is notified of the problem before tiling otherwise he / she might only lay on top of the concrete which would leave you back at square one.

WRITE TO US If you have a building- or renovation-related query that you'd like Steve to help you with, email doorstepdoctor@tribune. ie Steve Guerin is managing director of www. tradesmenireland. com, the onestop website that will help you find a tradesman, a site for sale, a property to rent or buy and all the plant hire and machinery you need to complete your house-build or renovation