Damp Proofing Mass Concrete Wall.

D_D

Hi all,

Just a quick one. Currently building a small extension on the back of my house and have an issue.

It's a terraced house and there is a party wall on both sides of the house which are 200mm mass concrete walls with foundations about 3ft into the ground. We got permission to use these walls by our neighbours on both sides, but I have a question on damp proofing there.

On the exposed side the builder dug as far as the foundation level to see if there is a damp proof course in the wall, but there doesn't appear to be any, so for peace of mind I would like to do my best to mitigate any potential damp issues.

I have looked into chemical injection but this does not seem to work that well in concrete.

Is there another method out there for damp proofing? Spray on barrier up to a certain height?

Thanks for any help.

PaleRider

It's a number of years since I have done this work in England. Back then we would call it Tanking. The ground floor and walls are plastered as one. This work needs to be completed in one day. The purpose is to create a water tight seal - that will work - even when under pressure. Also you cannot use nails anywhere on the sealed walls/floor.

I'm not sure who does it here in Ireland. Look to the damp-proofing companies. Check work done by them. This is specialist work.


Check with neighbors first to see if they have suffered damp problems. And what worked to solve them.

Again seek out Professional input.

D_D

PaleRider wrote: »

It's a number of years since I have done this work in England. Back then we would call it Tanking. The ground floor and walls are plastered as one. This work needs to be completed in one day. The purpose is to create a water tight seal - that will work - even when under pressure. Also you cannot use nails anywhere on the sealed walls/floor.

I'm not sure who does it here in Ireland. Look to the damp-proofing companies. Check work done by them. This is specialist work.


Check with neighbors first to see if they have suffered damp problems. And what worked to solve them.

Again seek out Professional input.

Thanks for the advice. I'll search for specialist help.

kkelliher

The actual layout will depend on how you can deal with this. If possible you will always want to tank from the outside of a wall to prevent water coming through the wall. There are system to tank from the inside of the wall but as they allow water to penetrate through the wall first before being removed, they are not ideal. For external tanking systems in my opinion you cant go wrong with Preprufe by Grace (http://www.preprufe.com/). They used be distributed through Brooks but went it alone a few years back and they had an office in Naas. It should be on the website.

Safehands

D_D wrote: »

Hi all,

Just a quick one. Currently building a small extension on the back of my house and have an issue.

It's a terraced house and there is a party wall on both sides of the house which are 200mm mass concrete walls with foundations about 3ft into the ground. We got permission to use these walls by our neighbours on both sides, but I have a question on damp proofing there.

On the exposed side the builder dug as far as the foundation level to see if there is a damp proof course in the wall, but there doesn't appear to be any, so for peace of mind I would like to do my best to mitigate any potential damp issues.

I have looked into chemical injection but this does not seem to work that well in concrete.

Is there another method out there for damp proofing? Spray on barrier up to a certain height? Thanks for any help.

You can tank with any number of waterproof slurries. Best done on the outside, but applying on the inside will also work. Any old paint must be removed totally first. As previously advised you cannot puncture the coating. Try googling a material called "Eproseal". I have seen that used by damp proofing companies.