Pointing

Loganfire

I have a builder who has just started today to re-point the house he seem to know what hes doing but is there any thing that I should look out for at the moment he's using a 2to1 mix as the original mortar is very sandy most likley 8to1 mix. I was hoping that the re-point would be a little more flush with the brick but is this me just being picky?

MX5huggy

2 parts sand to 1 cement? ! This is far too strong, yes your pointing will last for ever but your bricks (if we are talking stone then its even worse) will be destroyed over the years, the pointing is supposed to be slightly sacrificial taking the frost damage and weathering instead of the bricks.

http://freespace.virgin.net/hearth.nireland/Portrush%20restor.html

There was no doubt about the condition of some of the bricks:but there was debate about why they were so bad. In fact, they were by no means uniformly bad, and many of the upper bricks were quite sound. The grey pointing sitting proud in the above picture tells the story - where the bricks had been left with their original lime pointing they were generally good, but where they had been repointed in hard cement mortar they had spalled with frost and possibly salt damage, often leaving the new mortar sitting proud of the spalled face.

Loganfire

I thought in most case the stronger the mix the better, normally i been told that 3in1 is acceptable when pointing brick however using 2in1 just make the mortar even stronger and less prone to weathering.

MX5huggy

That is the common misconception. But all strong pointing will do is damage the bricks which will cost far more to replace than the pointing in the future.

iamcornholio

The mortar needs to be flexible to cope with natural movement and expansion of the wall. Too strong and it will crack and will either fall out or cause the brick edges to erode due to frost action

The weathering protection (ie strength) of the pointing is achieved with proper ironing and smoothing of the joint and not by making a strong mix

The mix ratio will depend on the softness of the brick and existing mortar, somewhere between 3:1 and 5:1. Definitely not 2:1

Your builder needs to rake out the joints to 20mm minimum 25mm maximum

Loganfire

With having a sandy mortar already hence the pointing would i be better off with a 3in1 or a 4in1 mix I guessing this is like 3 sand and 1 cerement? Also does cerment come with lime already mixed into or do you need to add this to the mix.

Loganfire

Spoken to my structural engineer (lol was on holiday)and my builder both said should be ok because of the age of the building and the type of bricks however the builder has offered to take out what he's done today and go with a 3in1 mix for no extra cost even though I offered to pay him