Repointing work

[Willy87]

Evening all got some repointing work carried out on my property in the summer builder used a 5 in 1 building sand and cement mix. After the heavy rain at the weekend wall looked all wet which is normal I assume just wondering if his mix is absorbing the rain thanks

 

[^woody^]

How the joint is ironed gives it the weather-proofing, not the strength of the mix

 

[Willy87]

Thanks so you think the repointing has nothing to do with how wet the wall gets when it’s heavy rain

 

[^woody^]

No. All walls will get wet and eventually saturated in heavy rain. The mortar and how it's finished is a significant factor in this process.

 

[Willy87]

Wall seems to dry out quickly after being saturated with rain so does mortar hold moisture aswell my worry was if it absorbed to much it would leak in

 

[Diver Fred]

It all depends on how porous the Bricks are, how long they have had to dry out etc.

 

[Willy87]

Bricks are pre war commons I believe. Just got shock when seen how wet they were was worried would soak right through to cavity wall insulation

 

[^woody^]

The way walls perform in rain can be interesting , but once saturation occurs, or even any dampness, the time it takes for the wall to dry off is the same for any given ambient air condition. i.e it does not matter if the wall was saturated for one hour or one day, as once the rain stops the wall will dry off in the same amount of time.

And once a wall is saturated, rain tends to run down the face not through it.

 

[Willy87]

Great thank you does this also apply for the mortar once it’s saturated then doesn’t go any deeper through the mortar just runs down it. I’m learning and finding it quite interesting how a wall functions to be honest

 

[^woody^]

A saturated wall means the brick and mortar, and it will be saturated to the back of the leaf in the cavity, where it then runs down, and hopefully not across.