According to a home improvement report by HSBC bank, 52 percent of Britons schedule in some DIY for public holidays. Picture: Karen Sandison

There was another great crop of questions this week, so let’s see what we can do to help.

Bash writes: Please give me advice re a new floor I had installed by a private building contractor. I had my existing Oregon floors lifted and replaced by a new African mahogany floor. After the first few strips were fitted it made a terrible squeaking noise. The builder lifted the strips and decided to first lay a decking board. That seemed to solve the squeak problem.

“A month later the strips seem to be bulging and we can’t get a reasonable explanation as to what is causing it. The builder insists that the wood strips are stretching and expanding and wants to wait a little longer to cut at the ends. In some (instances), the wood seems to have bulged up by at least 30cm in quite a few different areas in my lounge.

Please give me a reasonable and logical explanation as to the cause and remedy.

Answer: The first question is why you decided to change the floors in the first place. If they were rotting or sagging, did you tackle the problem causing the damage?

In a recent article on African mahogany I wrote that although the wood is reported to retain its shape well after seasoning and shows only small movement in use, it can warp when exposed to the sun.

I presume that when you say the floor was installed by a private building contractor, you chose a floor specialist.

Was the new flooring left to acclimatise where it was being laid? New flooring should be left in its new home for six weeks before fixing into position.

Regarding the initial squeaking, possibly it was not being secured correctly, but more likely, the flooring was too thin to span the existing joists, or conversely the joists are spaced too far apart for the thickness of flooring.

I would never recommend laying a decking board first. It might stop the squeaking, but it has also blocked the floor’s ability to breathe. Suspended timber floors need to have air circulating around them continually. If you’ve had the floor sealed as well, then any residual moisture in the timber has nowhere to go and it will start to swell and bulge.

You say the floor has lifted 30cm. I’m sure you mean 30mm not cm, but even that is excessive.

Time may be the answer to your problem, but I am still concerned about the decking board. I don’t like to say this, but you may well have to start again. Hopefully you have not paid for the floor yet and will have some means of applying pressure on the builder.

And now for something completely different – a question from James, a contractor who writes: “I have recently repaired a floor screed for a client. They wanted a five-year guarantee on this. Am I obliged to give them the guarantee?”

I would never undertake any work before the rules of engagement have been set, as it is difficult to compromise afterwards.

In general I would not give a guarantee on minor repair work. In your case, what is going to happen if the rest of the screed fails, which in my opinion is likely?

If no agreement was made before you started work, then you are not obliged to give a guarantee. If however it is now a case of obtaining payment after the fact, I would give no more than a year’s guarantee and would advise that you confirm in writing that the guarantee applies strictly to your work only and to the areas you have worked in.

Brian asks: We had our west-facing windows changed from wood to aluminium a couple of years ago. When it rains the water drips on to the downstairs walls and ruins the paint. I have had the upstairs windows sealed a couple of times, but it does not seem to help for long. As far as I can ascertain the water is coming down through the cavity between the bricks. What’s the solution?

Answer: This is another common problem. With aluminium windows you get what you pay for – there is no comparison between cheap and expensive aluminium windows. If the windows are cheap, it means thin and lightweight sections are being used. More expensive contractors use heavier sections with sub frames which ensure that leakage around the edges is minimal or non-existent.

If there was no leakage before the installation of the aluminium windows, it means the pre-existing damp-proof membrane was not properly reinstalled when the aluminium frames were put in. It is very easy to tear membranes when taking out the old timber windows, and if a sub-frame is not used, it is difficult to seal the old damp-proof course to the new aluminium. All too often standard-size aluminium windows do not match up to the sizes of timber windows, which means either an excessive amount of existing brickwork and plaster has to be hacked out, damaging the damp-proof membrane, or excessive plaster has to be used to build up a large gap around the window, which can easily bypass the membrane.

There is no easy cure, as any silicone sealer at the joint between the new window and old brickwork will always break down over time. Ideally you need to open up a good-sized gap, pack it with an expandable sealer, replaster and seal again.

I’m more concerned that water is penetrating from the top floor to the ground floor. It would seem that the damp proofing in the cavity at slab level has failed, or may always have been poor. Sealing the leaks correctly around the windows should negate this problem.

It is also possible that the installation of the new windows has caused other cracking in the walls, or that cracks have just developed. Check exterior walls for signs of cracking. Open them up, seal them and then paint the entire wall with a weather-proof paint system. - Weekend Argus

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