Lime and green

With the final smooth coat of render being to the the bedroom extension this week we've followed the builders advice and started painting the external walls before the scaffold is removed.

We've considered two external masonry paint options, both from the Greenshop. Silicate paint was our initial choice as it's a long-life solvent free and breathable paint. But after discussing the nature of Hillside,and in particular the problems we've had with damp in the original cottage, we've been advised to use a lime-based paint.

So we've bought a load of Stuart Furby's lime earth paint. The paint comes as a two-part system comprising a bucket of lime slurry, which requires a good mix before using, and bags of non-hydraulic lime with the chosen natural pigment. We've opted for 'Pale yellow ochre' which is not dissimilar to the existing cottage colour, albeit much cleaner!

On the new render we've used the white lime slurry as a primer to avoid having to use excessive coats of the more expensive finish colour. As this only requires a good stir before using it's not that unlike conventional paints, albeit rather watery. The caustic nature of lime does mean you have to wear rubber gloves to protect your skin from splashes, along with safety specs for eye protection, but it's good there are no VOCs or other petrochem products to breathe in.

For the second coat we've mixed in the colour which is more of a challenge. We used a spatula that we found in the shed but the manufacturer recommends a whisk which we'll use for the next pot, as it's a challenge stirring the bags of non-hydraulic lime into the slurry. Coverage has proven to be about what they claim on the tin, 1 litre for 5m2, but we do need to do a second coat in most places. Hopefully the old render won't need as much except where it's badly discoloured.

We applied the paint by brush, as recommended, and not by roller. This has undoubtedly made the job more effort but we don't think a roller would apply the lime paint as well as a 'conventional' paint.

We've only done two walls so far but they're looking good.