Rising damp, possible DIY?

[Sebastian90]

Hi there, we have a damp issue in the masonry under the existing membrane. A quote for repairs of "injection of new Dampcourse barrier" are going to cost around $2500. Just wondering if anyone has experience doing this themselves, or if this is one of those better call an expert situations? Attached is an example of the issue.

Thank you!

[Jewelleryrescue]

Hi @Sebastian90

I think you all ready know the trick is to angle grind out the old soft mortar and replace it with more water proof mortar Admixtures.  Older methods used to be a sand cement lime mixture the lime helps water to leach out. But mortar Admixtures  or  injecting the wall with  waterproofing solution or drilling holes and inserting dryrods which react with water and seal the area is the more modern way.  As well as the plastic water membrane you have.

The other question is where the water is coming from ?  Wicking up from the ground?  Or yesterday  my neighbor showed me a hole in his roof and water was running down sarking in his roof to inside the wall lucky he also had planned weep hole open( no cement) mortar slots every 3rd brick to let the water out and air in when the roof is repaired soon.

You have two choices here the simplest option is as a  DIY home owner option to simply refill the gaps in the mortar and make the wall look nice with an admixture water proof mortar may repel the acid effects  of ground water and salts.  There are also high strength structural mortars available at Bunnings But for a  normal house standard mortar only needed. Just remember to match your mortar color and  spritz  the brick work wet with  water as you add the new mortar to get it to bond to the bricks better.

Or a solution left more for a  very advanced DIY person if the old mortar really badly  crumbling dig it out and replace it the width of the brick you might use a large refillable caulking gun to pump the new water proof mortar deep into the  brick wall easier than trying to trowel it in.

I would grind out the mortar 6 brick sections at a time at different locations around the house to speed things up using a large angle grinder and or a cheapie / old flat blade wood saw is good for raking out old mortar ( naterally if you ground a long continuous section of brick work the wall will want to collapse down wards. So  do short sections at a time the wall should  support itself.

Specialist companies drill holes in the wall and inject a sort of silicon based liquid that soaks into the brick work making it water proof. But in your  wall the mortar looks like it could be replaced with a Admixture cement based mortar as the mortar its self looks crumbly?

[EricL]

Hi @Sebastian90 

@Jewelleryrescue's advice is spot on. If you are after an alternative regarding the rising damp, replacing the old mortar with new mortar along with an admix additive such as Gripset Betta 15L Admix Super Concentrate will enhance the adhesion, strength, waterproof properties, shrink resistance, salt resistance and general improvement of the cement.

Doing it in sections means that you won't be overwhelmed by the repairs. 

If you have any other questions we can help with, please let us know.

Eric

[spacessound]

You don't have a problem unless the DPC has been installed incorrectly (above the finished floor level or some other problem that we can't see from this photo). Moisture in brickwork below the DPC is completely normal (bricks and mortar are porous and will absorb moisture). As the the mortar seems a little degraded, all you really need is a little repointing with normal mortar - no heavy cement content or any special admixtures.

[EricL]

Hello @spacessound 

Welcome to the Bunnings Workshop community. It's wonderful to have you join us.

Thank you for sharing your knowledge and experience with our community regarding the DPC and rising damp. It looks like you've dealt with this issue before.

We're keen to hear more about all your projects and plans around the house and garden. Please feel free to reach out whenever you need assistance or would like to share a project with the community.

Again, thank you for sharing your experience with the community.

Eric