Brand new house - Rising damp issue

Hello All,

I have just signed a contract with highly reputed builder for a ready built home. We had our budding inspection today and the inspector found 1 major issue related to rising damp on the exterior walls.

the inspectors comments were - Salt residue ( efflorescence ) on lower level external walls is visible. Salt residue can be associated with rising damp problems.
Recommendations: Further investigation by a specialist in this field is strongly recommended.

The house was built on H1 soil using waffle slabs and its double storied house. Also, the house is on a slope, the building on the rear of the house is around 3 meters above the ground level of the inspected houses. We also found the same rising damp issue in the house next door, which is also brand new and build by the same builder.

I would like to know if this issue can be fixed and would it affect the structure of the house in the long run? The builder is giving me 50 year structural guarantee, but I am not sure if this issue or any future issue related to the rising damp would be covered in it.

If this is going to be an ongoing issue, we are looking at terminating the contract.

Please advise

I’m no expert on rising damp...but I would digging down under bricks alongside concrete slab (go fairly deep into soil) and see if they maybe forgot to install the plastic membrane that should e underneath the entire concrete slab to stop moisture from the soil through the concrete and into the building structure.

Thank you so much for the reply, I found this note from the inspector in the report, any thoughts on this??

Damp Proof Course
" A damp proof course (DPC) was noted'

The DPC is the (typically) black plastic strip that is installed below the course of bricks that also include your weep holes. This in theory will prevent moisture migrating via capillary action from below this level to the brickwork above. But it’s main purpose is to provide a water barrier for moisture trapped behind your brick wall....hitting the DPC and evaporating or draining out via the weep holes.

The plastic membrane I was referring to is layed over the soil, prior to the concrete being poured.....well there are other things that happen before concrete pour but you get the general idea hopefully. This plastic separates the ground moisture from rising through into the concrete foundations and building structure.

This membrane may have been installed but not correctly...maybe it didn’t come up the sides of the slab adequately and this has allowed water to seep into the base of the concrete?

Maybe inspect the bare concrete in the garage to see for any visible issues there?

Are the bricks concrete bricks,hard to tell with photo,if yes then concrete bricks are much more porous.

Thank you Darb, I will have a look at the concrete, when the inspector checked for mositure on all four sides of the garage, it looked fine..

I want to know if there is specialist who can check and give me a green signal about the purchase or suggest a long term solution for this. I hear a lot of rising damp stories on H1 soil with waffle slabs and I don't want mine to be another one.

Should I refer this to the plumber/ landscaper or damp specialist?

Hello Joker, Looks porous bricks to me, I have attached some high resolution photos.

My project manager builder who builds from beginner up to architectural homes says he never uses concrete bricks as they soak up moisture and don't last as well, ask Alex79 or insider or saveH20,building expert, Any can give a true reflection of what to generally expect from concrete bricks.

Generally concrete structures in contact with damp/soil require waterproofing.

The plastic membrane under the slab (and footings) protects damp from getting into the house, but looks like your issue is rather on the external walls, so theoretically should be handled with DPC, but also the lowest brick would have to be waterproofed as it stays in contact with the soil.

Can you do some minor digging and take a photo at the actual connection between one of your affected bricks and the slab?

Where was it noted? The concrete looks high to me.

It's was noted on the exterior walls of the living room which faces the backyard. The inspector made a special note on the salt deposits on the bricks which is at the foot of the fall.

Yes I can, I have requested the builder for an independent inspection, but I am not sure whom to ask, damp experts says it's not their job. Should I see a plumber or a water proofing expert to carry out this inspection ??

Possible it's the water trickling over the window sill and leaving salts deposits , have you got other brick window sills with same efflorescence issue underneath?

Because if you look at the aluminium frame it too has what looks like white powdery salt deposits , possibly from water trickling down from above?? Just a theory.

The white stain seems to be originating from the grout, I think it’s called efflorescence and is commonly associated with concrete bricks. I think you can get a product at hardware stores to get rid of this stain and seal the bricks. I don’t think it’s rising damp.

Thank you for the reply.

Thats an interesting point, I had a look around the house, its there in another place as well but there is no window or aluminium frame there.

This is exactly what the agent and the representative from builder said and he said it is very common with such types of bricks.

I just want to have some piece of mind, where some one " licenses inspectors" assess it and confirms its just a brick issue.

Why not get a treatment for efflorescence, if it continues to come back or you notice other evidence, then request another inspection. Have a look when it rains as well and see where the water is trickling.

From my experience the efflorescence is a results of excess water then drying which leaves the residue so the problem may not be there now.Was it a wet period during the construction with poor drainage and no temporary downpipes?
I would get a soil test next to your perimeter wall with soil moisture content testing from a geotech company.I noticed you have pebble landscaping, this is a bad idea especially with a H1 soil type.The pebble landscaping will allow water to penetrate into the ground and then restrict evaporation gradually leading to an increase in soil moisture around the perimeter of the house.Apart from rising damp this can lead to slab heave, I would remove the pebbles and either grade the soil away from the house or place plastic down which grades way from the house and then put landscaping material on top.

I am still in the pre purchase stage where I have signed a contract and I have building and pest condition for 21 days, I have another 14 days left to arrange an inspection done by a specialist and find out what the issue is and also suggest a remedy. The builder says there is no issue but he is happy for us to do what ever tests within the next 14 days.

If you can suggest if I should engage a plumber ? Damp specialist? Concrete specialist? Or a structural engineer then i can take the next course of action. At the moment I am not sure whom to consult