Sealing Concrete Floor-Wall Joints

Sealing Concrete Floor-Wall Joints

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Discussion

Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
Hi!

We have an ongoing issue with moisture low down in parts of internal walls and have been advised that the solution is to form deep seal
floor joints/fillets.

Does anyone have any experience of this, or know of someone who would be able to advise and do the job?

Any help would be greatly appreciated.

Jazzer

Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
Anyone??

C Lee Farquar

4,068 posts

216 months

Sunday 26th June 2022
quotequote all
It depends on the age of the house and what defect you're trying to overcome.

Also, is the problem on completely internal walls or the inside of an external wall?

Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
It’s a 1950s house with concrete floors and solid walls. There is low-level moisture on parts of internal walls (rooms either side).
The DPC is being bypassed, so walll-floor joints and plastering are being looked at.

KnackeredOldBanger

251 posts

89 months

Sunday 26th June 2022
quotequote all
So your solution is an injected DPC and salt retardant plasterwork? Although someone will be along to tell me I'm talking rubbish soon enough

Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
The chemical DPC treatments (nite the plural) did nothing. The DPC is present, but is being bridged. We’re looking to remove plaster to expose the DPC , and seal floor-wall joints.
It’s this latter aspect that we need advice and direction on…..it’s hard finding someone with experience of this who can do the job!

C Lee Farquar

4,068 posts

216 months

Sunday 26th June 2022
quotequote all
If a CDPC has been installed then the accepted practice with a solid floor is to tank (google Vandex/Thoroseal) from the floor to the new DPC. This is a simple DIY task, you mix it up and brush apply.

However, a CDPC in a 4" wall is largely ineffective, it's usually not possible to diffuse a meaningful amount of fluid in such a narrow mortar bed.

Another way of dealing with the issue is to fit taller skirting with a small air gap below, hacking off the plaster to just below the top of the skirting. The theory being that the original dpc, although bridged, is only going to allow minor damp to bypass it. This method allows the moisture to evaporate naturally.





Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
Thank you for taking the time to reply in such detail, you know stuff!!

We will remove plaster to above DPC level, just below the height of the taller skirting, to allow moisture to evaporate better,, as well as sealing the joints.

This should work!

C Lee Farquar

4,068 posts

216 months

Sunday 26th June 2022
quotequote all
Bare in mind I haven't seen it so I am making some assumptions!

Don't tank up the wall, leave it as exposed brick behind the skirting. If using timber skirting coat the rear with a fungicide before fitting. Use plastic spacers to fit the skirting, not timber packers.

You're aiming to allow minor damp to evaporate without rotting the skirting and avoiding the damp staining your plaster. The risks to the fabric if it doesn't work are minimal (you have no timber floor structure that could rot).




KnackeredOldBanger

251 posts

89 months

Sunday 26th June 2022
quotequote all
Jazzer said:
The chemical DPC treatments (nite the plural) did nothing. The DPC is present, but is being bridged. We’re looking to remove plaster to expose the DPC , and seal floor-wall joints.
It’s this latter aspect that we need advice and direction on…..it’s hard finding someone with experience of this who can do the job!
Did they hack the previous plaster off? And have they stopped short of the floor when they have replastered?

Jazzer

Original Poster:

1,674 posts

204 months

Sunday 26th June 2022
quotequote all
This makes a lot of sense, we’ll give it a go for sure!👍

wolfracesonic

6,996 posts

127 months

Sunday 26th June 2022
quotequote all
Are,you doing the work yourself OP? Maybe worth trying some of these Dryrod dpc, whilst the skirting is off, not overly expensive and if you can drill a12mm hole, you can install them.

Jazzer

Original Poster:

1,674 posts

204 months

Monday 27th June 2022
quotequote all
I would rather have someone who knows what they’re doing do the work, and would happily pay.

I’d never again employ the usual cowboys, who just want o inject and cover up problems for a few months, without taking time to establish what the underlying cause is.

We’re based in Essex, so if you know or can recommend someone, please let me know.

Thank you for these very helpful replies.