A quick ‘Green Man Building Building Company’ guide to re pointing:
It is essential when working on period buildings, that the make up of the existing mortar is taken into account in terms of texture,ingredients and colour.
Take time to find out about your building, the texture ,size and colour of the brick,its age and the make up of the mortar.
Analysis of the existing mortar will provide information that will guide the mixture of the new lime mortar and help to achieve a close match,not only in colour,which is the obvious one, but strength absorbency and texture which will aid durability and the all important breath ability.
The new mortar does not want to be too strong,especially important when working with the traditional low fired period bricks as a strong mortar will lead to erosion of the brick,spalling and other issues such as cracks running through the brick, rather than the ‘sacrificial’ mortar.
Important too to ensure that the joints are raked out to the appropriate depth( at least 1 ½ times the width of the joint), flushed out with copious amounts of water to remove dust and the whole area to be re pointed dampened prior to staring work.
The re-pointing will cover a good area quite quickly,so an organised approach to dampening is essential,especially in the summer months.
After pointing and the subsequent jointing up of the mortar the wall needs to be kept moist by covering with hessian which can be lightly sprayed over to retain the moisture-rapid drying will ruin the results and the whole thing will have to be started again!
Keep it covered and damp( NOT wet) for a couple of days at least in the summer.
It all sounds simple and indeed, with preparation, practice and patience the novice can achieve a reasonable result, but do practice on an area that is not in full view first!
This is but a quick guide, more advice on request from :
THE GREEN MAN BUILDING COMPANY LTD