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After trying many options to fix a maintenance issue, Mac concedes that the last word counts

This week we are looking at the different methods of removing loose or flaking paint from surfaces to be painted.

Depending on which area you are working on, and the location of it, we can select our tools.

Interior and external areas must be treated differently because of the amount of mess to be made and the ability to clean it up easily.

In Cape Town initially, and now around the country, we have problems with using water to clean the exterior of buildings, so before you let loose with a pressure water-jet cleaner. please ensure you have a supply of non-potable water to avoid wasting one of our country’s most valuable resources.

High pressure water washing is going to make a mess and the clean up is not going to be easy. This may not be the best option for around your home, especially if your partner has a beautiful garden at the foot of the wall.

Also avoid this method if the existing paint surface is powdery because the water is just going to turn it into a mushy paste.

So now that I have convinced you not to use a water jet domestically, what should you use?

Attack the loose and flaking areas with a flat paint scraper, working slowly to ensure every last bit of failed material is removed.

Once most is removed, especially on powdery surfaces, it’s time to get stuck in with a hard wire brush, again a really messy exercise, but unless you get the underlying surface solid you are wasting every cent you are going to spend on paint further down the line.

Be careful with walls that have had a creeper growing against them.

This is really going to be hard work. You may well need a blow torch and could end up with a lot of loose plaster.

Unless you have a pet hate of creepers and there is no damp on the inside, you should rather let it alone.

Q and A

Malthoid is often used for waterproofing between the tiles on a roof. Picture: Tom Hain

Jutta, who writes to me regularly, has been having problems with her roof and wants to know: 

Q: What is the “lifespan” of the membrane, generally?

A: She is referring to the malthoid membrane which is used as a soaker course between the courses on a natural slate roof, usually referred to as a mazista slate. In my mind the jury is still out on which is the most attractive roof covering, natural slate or a genuine clay tile. Both items are usually imported and tend to be expensive, so you want a roof that is going to last.

Back in the day, houses were built with steep pitches so large slates were used with no underlay. With a steep pitch and large slates, the water rapidly ran off. However, as costs increased these slate roofs just became too expensive to build. To reduce costs the pitch was reduced and the slates made smaller. 

This meant a waterproofing layer had to be inserted and malthoid was used. The problem comes with the effect of UV radiation from the sun on the malthoid. 

The malthoid is exposed between the slates and thus subject to the effects of UV, which over time will break down and allow rain through. This will take about 20 years. Once the roof starts to leak it is difficult to trace the source of the leak as the water will penetrate the first layer, run along the next course of malthoid underneath and come out at the next weak point.

Over the years other materials have been used under the joints to protect the malthoid with some success. Having said that, this is a 20-year-old roof, so are most other roofs depending on geographical area, materials, maintenance and so on. The big word is “maintenance”, so spend your time looking after the top layer of your home.

In a new build, do serious homework on what works in the area in which you are building. If you are buying an existing home, spend on a professional opinion about what you are buying.

Tip of the week

Attack flaky or loose paint with a flat scraper and avoid water jets. Picture: Roger Bradshaw

This week we are looking at the different methods of removing loose or flaking paint from surfaces to be painted. Depending on which area you are working on, and the location of it, we can select our tools.

Interior and external areas must be treated differently because of the amount of mess to be made and the ability to clean it up easily. In Cape Town initially, and now around the country, we have problems with using water to clean the exterior of buildings, so before you let loose with a pressure waterjet cleaner. please ensure you have a supply of non-potable water to avoid wasting one of our country’s most valuable resources.

High-pressure water washing is going to make a mess and the clean up is not going to be easy. This may not be the best option for around your home, especially if your partner has a beautiful garden at the foot of the wall.

Also avoid this method if the existing paint surface is powdery because the water is just going to turn it into a mushy paste. So now that I have convinced you not to use a water jet domestically, what should you use?

Attack the loose and flaking areas with a flat paint scraper, working slowly to ensure every last bit of failed material is removed. Once most is removed, especially on powdery surfaces, it’s time to get stuck in with a hard wire brush, again a really messy exercise, but unless you get the underlying surface solid you are wasting every cent you are going to spend on paint further down the line.

Be careful with walls that have had a creeper growing against them. This is really going to be hard work. You may well need a blow torch and could end up with a lot of loose plaster. Unless you have a pet hate of creepers and there is no damp on the inside, you should rather let it alone.

If you have a question for Don, send it to don@macalister.co.za or SMS only to 0824463859. 

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