Questions and Answers

Here are some questions which I have already been asked; who not sign up in our Yahoo email group where you'll find lots of others who are willing to share their experiences and discuss any problems you may have (see the "Join our Email List" page by clicking on the button at the side).

Distemper v Whitewash
You imply in the book that distemper is the ideal type of permeable paint for inside use, yet whitewash is still commonly used. Does it have any advantages or are people just slow to change their habits?

Whitewash hardens by a chemical process caused by the absorption of CO2 and atmospheric moisture. When this process is complete - after 7 to 14 days - a further coat can be applied without appreciably softening the first, so the result becomes increasingly smooth. Distemper is always softened by a successive coat, and so cannot be built up in this way; also, it is more readily affected by damp conditions. However, as it can be applied to a wider range of surfaces, it is more suitable for inside walls which have been repaired or added to with cement render.

That PVA problem
Like you, I have found it impossible to obtain PVA in Spain. You suggest that it might be worth trying wood glue in an emergency. Have you actually tried this?

I have - and it works. I used the Unifix brand, at around 6 Euros per kilo from larger hardware and paint shops. It worked fine, but that’s over double the usual UK price from budget suppliers (although little dearer than the brand leader, Unibond).

Cement or Lime?
I am still confused by your equivocal position on repairing crumbling stone walls with cement mortar rather than lime. Can you please clarify.

I faced the same dilemma myself on several occasions and have used both lime and cement under different circumstances. In my opinion, repairs with cement lead to problems only if the wall is known to be damp or unstable, or (and this is important) a thin and poorly adhered coating is applied: the mortar must extend well between the stones to give a degree of structural support if it is to have lasting benefit. Even so, watch out for hairline cracking and ensure that these are properly filled. Lime is a safer option but requires more skill and patience, and is the only answer if the wall is less than perfectly dry and stable.

Damp interior wall
An area at the foot of one (internal) wall is below outside rock level and is slightly damp. I know this because the paint constantly flakes and bubbles away. I have chopped away the crumbly top surface and have come to a layer of lime and sand which is slightly blackened. How should I proceed?

This is what I did in similar circumstances. I scooped out some of the thicker lime at the bottom of my slaking barrel, and mixed it with dry sand (I found that damp sand resulted in too wet a mix), in the proportions of 1:3. This was trowelled into place and sprayed several times daily for a week (to reduce cracking). After a further week it changed from grey to white. A further coat of limewash was applied. This provided a completely effective cure, which has given no further trouble.