Need to point up the top of our walls. How can I tone down the lime mortar mix?

Property & Home
1

Hello all. We are nearing the end of our renovation on a Charentaise longere. On the rear North(ish) facing elevation the stone walls have been pointed but a long time ago. Most of it is sound so I have no intention of redoing the lot as the area is huge...23 metres wide by about 6 metres tall!


At the top of the wall where it meets the overhanging roof the stonework doesn't go right up to the underside of the roof boards. I want to build it up as we have plenty of limestone rocks. I figure if it is sealed up it will reduce drafts/noise. Also it will be harder for various furry beasties to get into the structure of the roof. We built the walls up fully on the inside of the house before the grenier was dry lined, insulated and turned into bedrooms/bathrooms. However it is still a bit drafty behind the dry lining?


The roof is a newer mechanical tiled roof and it was done several years before we bought the house. There is no membrane (French roofers?) but the roof is sound and watertight. Next to that is 200mm of Knauf glass fibre insulation and then plasterboard.


So to my question!! We have used Tradifarge lime and cement mix and the local sand which when mixed 1 part Tradifarge to 3 parts sand gives a very light grey, almost white finish to pointed stonework on the interior. This works very well with the cream coloured local limestone. However if I use this on the rear exterior wall of the house it will stick out like a sore thumb. What can I add to the mix to tone it down. I want something that can go in the mix?


Any thoughts?



Cheers Paul


2

Parexlanko is a Cement (OPC) based mortar

3

I am sure any Frenchman would agree with you and so would I especially if the wall is at the back of the house where its unlikely to be seen from the road. In my experience dealing with BdF is a nightmare and they are very intransigent once they have made a decision it is impossible to get them to change it. The work is not structural and thus will not require any other approvals as far as I know nor will need to be declared if the house is sold.

4

No, not all are listed, but easy to check at the Mairie.

Having said that though, if the OP is filling in the gaps at the top of his, already pointed, walls and is matching the original pointing, why does he need to ask ABF? lol They'd probably tell him that the whole lot would need to come off and be repointed in a different shade!

5

Not entirely sure about this. I was told it was just a church but most are very old and therefore likely to be listed as well. In our case we are opposite a 1200 year old Abbey so no argument.

6

I was told that you only have to inform Batiment de France if, as you say, you are within 0.5 km, AND the building is a listed monument. All churches are listed?

7

Actually mixing the various components is very easy once you have done the first mix to get the colour right.

It may be important to consider whether or not Batiments de France need to be advised of the repointing. If your house is within 0.5KM of a church or ancient monument BdF have to approve any external changes to the building and will dictate the colour of pointing or rendering according to local norms. That said many (probably most) French owners do not inform them and little happens. You can tell the "local colour" by walking around and seeing what most houses have used for rendering or pointing. Its usually a bit more sandy or yellow than white.

8

You could go to your local builders' merchants and ask for a colour chart for the LankoParex ready mix, then match with what's already there. Easier than trying to mix lime, sand and colours mixers..

http://www.parexlanko.com/fr/documentheque-produits/facades

9

Hi Paul

Have a look at this thread

http://www.survivefrance.com/forum/topics/re-pointing-cellar-interior-wall-advice-please

I made a few comments myself about the mix and methods of pointing.

I endorse Edward Byrne's comments strongly. If you use cement in pointing for stonework the pointing will be harder than the stone and when the wall moves (as it inevitably will) the stones may crack and/or the pointing fall out. Lime mortar (NHL) is softer than the soft limestone or sandstone used in most of SW France.

You can mix the correct colour by using different colours of sand and once you have the recipe it is easily reproduced. I haven't used tints but I suspect they are much trickier to manage and get repeatable colour on successive batches. The mix is important as is the time you mix. Use a mixer it is very hard to mix for 15-20 minutes by hand. Don't buy the expensive premixed mortar (most has cement in it and it costs x5-6 using separate sand and DHL)

Take you time and be careful on the ladders!

10

You can buy powdered tints (cream, red, black, etc). Try Leroy Merlin or Castorama. They are designed for lime/plaster/cement .

11

Would something like this work ?

http://www.toolandfix.com/bond-it-cement-colour-dye-mortar-tone-powder-1kg.html?utm_source=google_shopping&prod_id=44946&gclid=CIT2g_fWjssCFeQp0wodCpIM0A

12

Use a proper Natural Hydraulic Lime eg St Astier NHL 5 or NHL 3.5 with a good sharp sand

Never use OPC ( Cement ) or Gypsum based mortars on traditional buildings always use an NHL

see www.stastier.co.uk for english specs

An NHL does not kill the colour of the sand like Cement OPC eg if you use a red sand you will get a pink mortar a brown sand will give you a fawn mortar