Author Topic: Stone barn - loss of mortar and pointing up. (Read 9250 times)

MAK · « **on:** April 10, 2012, 08:19:38 am »

Yesterday I noticed just how bad the loss of "mortar" between the stone is. I say mortar but it is more of a hard sand that can be scratched away. Last year a french builder told us that it was the bees that "ate" the mortar and certainly flies are attracted to the buildings because the old mortar is said to have organic debris mixed with it. We also have lizards running in the cracks but after a very cold and prolonged bout I wonder if this is due to freeze thaw.
Any thoughts -?
I can get my hands in between some stones and the severe loss of mortar extends from ground level to about 4 feet up. Time to get out the mixer and invite my son over for a holiday ( HELP !!).

robert waddell · « **Reply #1 on:** April 10, 2012, 10:52:22 am »

it is a lime sand mortar mix which does rot through time yes the bees do attack it a strong mix will bind it BUT REMEMBER TO WEAR GLOVES the lime eats into flesh you will have to do sample mixes first the good thing is you wont need scaffolding have seen this before with sandstone walls at the side of roads eaten away with salt

MAK · « **Reply #2 on:** April 10, 2012, 11:18:11 am »

Thanks Robert - good advice. I will probably use cement mix for the area that the pigs cn get to as this is at the end of the barn and out of site. There is always so much to do so I think I may help - maybe a woofer or get my kids to come out and earn their supper.

robert waddell · « **Reply #3 on:** April 10, 2012, 11:34:17 am »

it will look odd with two types of mortar the cement based one will stick to the stones and you will be cursed in the future

MAK · « **Reply #4 on:** April 10, 2012, 11:38:36 am »

true - maybe I should hold on a bit rather than crck on and use the materials I have.
lime mortar it is.

chrismahon · « **Reply #5 on:** April 10, 2012, 08:28:03 pm »

Lime mortar is naturally flexible MAK. Our 1830 house is held together with it. It allows for any ground movement and as such is weak. The builders here use a 'fake' version on Listed Buildings and in Conservation areas with a mortar mix of building sand, sharp (washed) sand, cement and lime which has the appearance of a traditional sharp sand and lime mortar with near the strength of a modern cement mortar. Trouble is I can't remember the exact mix volume ratios but I think it was something like 5 building, 3 washed, 1 cement, 1/2 lime. Bit odd really as cement reacts badly with lime when it is dry and cracks -my floor skimming went 2 days after it had dried! Cracked and lifted all over. Needed tilers (expensive) sealer -3 coats and then relaying.

Guess you need to test a bit MAK to see if you get a reaction. Stone is limestone in that area isn't it?

deepinthewoods · « **Reply #6 on:** April 10, 2012, 08:34:18 pm »

having had to learn quickly to finish a job im on, dont use cement at all. you needa proper lime mortar, made from lime putty thats well matured. im currently removing cement from a 1730's cottage and rerendering it, properly, the things that make cement good for new build make it bad for old buildings, lack of flexibility and being waterproof are the 2 worst things for an old wall.

FiB · « **Reply #7 on:** April 17, 2012, 10:10:51 am »

timely post as I'm just about to repoint the end of our house (which was a 16c cow shed) - what is your prefered 'recipe' Deep in the Woods? We have a mixture of cement motor and original (from when it was converted 20 yrs ago by prev owner) - and it does look a pig, so I'm going to rake it all out and start again. Hopefully wont have to do it for a while so may as well make a good job of it.... Cheers, Fi