How can I protect my home from the rain? Damp-proofing specialists can make sure your brickwork and cellar are watertight, but check past work, as chemical damp-proofing treatment scams are not uncommon. If you live in an area at risk of flood, then have your sockets and fuse boxes raised by an electrician. This may prevent the need for expensive rewiring later on. Flood boards prevent water coming in through gaps between your door and the frame. Larger DIY stores will have the marine plywood suitable for this and a handyman will be able to fit it. Make sure you temporarily cover up air bricks if there is a risk of flood, as these will let water in. Many people forget these and regret it later. You can buy special products to cover these. Don't forget sandbags. The simple solutions are sometimes the most efficient. Most DIY stores should stock them, but they can run out quickly if the forecast is for heavy rain. If your electrics are damaged, or you are worried about damage to them, then call out a qualified electrician. Electricity is dangerous at the best of times and you put your family at risk if you go for a cheap and easy option. If the worst does come to the worst, then make sure you keep receipts for any work you have done and always take photos of any damage, as your insurer may wish to see these. MyBuilder links home owners with customer-reviewed tradesmen in their area (mybuilder.com). For more tips, see environment-agency.gov.uk Avoid touting electricians Q We often get inquiries from electrical companies, asking if they can inspect the wiring and electrical installation of our 1964 bungalow, and quote for any work needed. We moved into the bungalow in May 1990, making a few changes and additions to the wiring, and observed that the wiring was plastic insulated and that the distribution layout was the old type installed in 1964, with wire fuses. We have had no trouble with the electrics and I can't remember when I last replaced a fuse. Would a modern distribution system offer a more sensitive response to an electrical fault? Might the companies offering this service be trying to get work that may not need doing, or does this sound distrusting of us? We are in our eighties and I am not sure we could endure the upheaval of rewiring the bungalow. FK, by email A You have every reason to be distrusting of firms or individuals who approach you unsolicited seeking work. As I warn readers on a regular basis, never, ever agree to have any kind of building work done by someone who knocks on the door, or puts a leaflet through the letterbox, or makes a "cold call" on the telephone. Simply ask yourself, "Why are these people contacting me - is it for my benefit or theirs?" Your home's 1964 PVC-sheathed wiring is most probably in good condition and there should be no reason to have it replaced. The lighting circuits might have only twin cable with no earth wire, which is still acceptable for plastic light fittings, although anything metal (such as some types of wall light) should really have earth cables added to them. You might also find it advantageous to have some extra socket outlets, or "power points," added to your existing power circuits - every home these days has so many more electrical appliances than were envisaged by builders in the Sixties. However, I would recommend that you do have your fuseboard replaced with a modern consumer unit with miniature circuit breakers (MCBs) and with the power circuits protected by a residual current device (RCD), which offers much better protection against electric shocks than the old fuses. But have this work done in your own time by an electrical contractor of your choosing, not by one who comes knocking on your door touting for work. Try the NICEIC on 0870 013 0382; niceic.com. Insulation issues Q I read in your column recently that one can have too much loft insulation. I have a large Victorian house with a slate roof, and I recently insulated the loft with approximately 10in (250mm) of new material, on top of the previous material which had reduced in thickness to 3in (75mm). I have since been approached by a company who surveyed my loft and concluded that I am entitled to a further 10in of free loft insulation. I thought this was great as I am sure there is considerable heat leakage from our loft, but your comments make me think otherwise. I would be grateful for your comments. AT, by email A The main problem with having too much loft insulation installed is that by keeping more heat in the rooms below, the loft space itself becomes cooler. This can lead to condensation problems in the roof space and, in very cold weather, freezing of water tanks and pipes. Insulation of 250mm of fibreglass or mineral-wool fibre is perfectly adequate. Doubling the thickness will not double the thermal insulation value, as the law of diminishing returns applies. Indeed, doubling might even result in a zero or negative effect, as this type of material can compress under its own weight, thereby reducing the volume of trapped air providing the insulating properties. The most troubling thing about your query is that this company, having surveyed your loft and found that it has already been insulated to a greater level than the recommended standard, has still tried to persuade you to allow them to add more insulation on top. It confirms my previous findings that many insulation companies have no understanding of the science behind thermal insulation, and are interested only in milking the taxpayer-funded subsidy system. This is a common and growing fraud that merits urgent government investigation. On the fence Q My neighbour has recently had a new fence put up between our properties (Thirties semis). A 5ft (1.5m) concrete fence post has been sunk into the ground and fixed to the exterior wall where the two houses meet, and bridges the damp-proof course. Is it possible that this could lead to problems in the future? I have read somewhere that anything attached to an external wall should be spaced away from it. PJ, by email AIdeally a fence post, or any other construction, should be at least 50mm or 75mm away from the house wall. This is not because of "bridging" of the damp-proof course (this is rare and much misunderstood by surveyors), but for two other very obvious reasons. One is that a post attached to a wall will never be a totally tight fit, but will leave a narrow and variable gap capable of trapping rainwater, leaves and other debris, and providing a breeding ground for insects and various invertebrates, as well as vegetative growth. All of these have the potential to cause dampness problems inside the building, and the tightness of the gap makes it impossible to clean out. The other reason is because of rain splash off the top of the post onto the house wall.If the post is in a sheltered position this might not be a significant problem, but good building practice nevertheless requires any fence or wall abutting a house to be fitted with a lead flashing dressed up the house wall to protect it from this source of moisture ingress.