Moisture ingress in below ground living area

[Merlot Mike]

Hi all, I'm keen to know if any of you can recommend a course of action. My lounge is partially below grade and just recently I have noticed some softness in the gib in just two small areas (this is gib on battens lining the concrete block wall). Presumably the original sealant on the exterior concrete block walls is starting to fail (the dwelling is approx 40 years old). From what I understand the best approach is to excavate at the external wall and apply new sealant etc. The foundation is only one meter underground I think and the wall about eight meters long. Can anyone recommend a good company for this job and any idea of what sort of cost?

[John the builder]

if the ingress is islotated you might be able to waterproof from the inside ? Remove some gib carefully to see what you are dealing with

[Merlot Mike]

if the ingress is islotated you might be able to waterproof from the inside ? Remove some gib carefully to see what you are dealing with

Thanks for your reply. There are three particular spots (approx palm sized) where the gib has been sort of bubbling/bulging slightly for a number of years but these were always solid when I pressed them. However last night I actually managed to make a persisting indentation with my thumb in each of those areas. All of the other random places that I have been prodding along the wall seem solid (and look normal too). So if I was to remove the gib and see, perhaps, a crack in that spot is that a good candidate for sealing from the inside?

[John the builder]

it is likely a leaks at the joint between wall and floor(or a block joint) rather than a crack. There are treatments that can work from the inside and can resist hydro-static water pressure or work to block the pathway for water.(talk to experts like Gunac waterproofing). coating whole of inside is best. If the problem is a general one then maybe excavation of exterior is the answer but more expensive because of the excavation and reinstatement required.

[Merlot Mike]

it is likely a leaks at the joint between wall and floor(or a block joint) rather than a crack. There are treatments that can work from the inside and can resist hydro-static water pressure or work to block the pathway for water.(talk to experts like Gunac waterproofing). coating whole of inside is best. If the problem is a general one then maybe excavation of exterior is the answer but more expensive because of the excavation and reinstatement required.

Thanks for the recommendation I'll call Gunac today.

Property Talkers, please relay any experiences you have had with the "seal from the inside" method.

[mrsaneperson]

I had water ingress coming in through the area where the ground slab of concrete meets the block wall , when their was a heavy downpour water would seep through.
I approached a number of tilers in the filed but there was only one with specialist knowledge that i ended up using. His name is Tony and he uses a special coating that is applied from the inside onto the breeze block or concrete . You can then put on tiles or in your case the Gib or ceiling battens.
It seems to have fixed the problem as we have had several heavy downpours with no sign of water coming through.
SURFACE TILING LTD
M. +6421 1634304
T. +649 533 5566

http://surfacetiling.co.nz/

[John the builder]

tilers would appreciate these prducts but this waterproofing is a specialist trade and not all products are suitable for all situations.

[mrsaneperson]

tilers would appreciate these prducts but this waterproofing is a specialist trade and not all products are suitable for all situations.

Yes very true. Most tilers i came across knew about waterproofing from the glazed portion of the tile so that water would not seep through but had little to no specialist knowledge of preventing water ingress by applying special hydrostatic solutions to internal block walls thereby preventing water seeping through an external wall that was hard up against soil.

[Merlot Mike]

I'm reading mixed reports on the effectiveness of internal wall treatment. I'm thinking of taking the external excavation approach even though it's probably gonna be expensive.. I'm waiting nervously for the quotes to come in.

[John the builder]

internal is the cheap option. If it doesnt work then you still have plan B

[Merlot Mike]

internal is the cheap option. If it doesnt work then you still have plan B

Hmm... yes that's true. But I while I'm fairly confident that the internal treatment will keep the interior of the house dry I'm concerned that the water still making it's way in to the blockwork will rust the rebar and cause spalling of concrete in years to come.

[Merlot Mike]

I'm also wondering what role if any the council plays here. Do they need to sign off on waterproofing work such as this?

[Incodo]

I suggest you check the cause of water entry before engaging someone with a vested interest is selling you their system. Our experience is that internal applied waterproofing is problematic in that it generally a) it does not stop water from entering the wall, only reduces the amount flowing out from it. You still end up with a cold wall because of the moisture in it and moisture in the air will settle on the cold surface ( dewpoint problem). b) some of the applications such as crystalline grouts require repeat application and while thye can reduce ( but often not eliminate ) moisture, if the wall has a crack subsequent movement can allow the backed up water to enter again. It is more than likely that because your gib is soft there will be a good fungal growth on the reverse face and often the dominant type is stachtbotrys . Be careful with handling that - MBIE has guidleines
Nutshell - identify real cause- there are NDT moisture meters that track moisture intensity paths in block, concrete and the like
Regards
Paul P

[klauster]

Each water ingress problem has its specific, so I wouldn’t comment. But consider this - water find its way and has a cooling effect. That causes even on dry walls dampness due to condensation (depend on season/temperature etc). I battled with different problems for years and only ventilation (at the out or in, or both) resolved the problems.

[Merlot Mike]

Each water ingress problem has its specific, so I wouldn’t comment. But consider this - water find its way and has a cooling effect. That causes even on dry walls dampness due to condensation (depend on season/temperature etc). I battled with different problems for years and only ventilation (at the out or in, or both) resolved the problems.

Was that an above ground water issue?