Improving the water tightness of a wall

[sometimewoodworker]

28 minutes ago, HighPriority said:

The OP stated that the mortar joints of the blockwork are poor.

Thats number 1 ingress point for water.

It sounds like the wall is 2-4m wide and the space from the neighboring wall is 200mm, so how about you let us all know how you propose to fill all those mortar joints prior to applying the paint or other membrane ?

As I have actually used the product I suggested, along with the MrFixIt version I am well aware of how to use it and what it will actually do. So no the mortar joints will not prove a problem and filling them is unlikely to be needed.

 

32 minutes ago, HighPriority said:

You’re an extremely infuriating man Jerome.

Why is that? Is it because when I actually know exactly what I am talking about, have used the products and know their weaknesses I don’t let incorrect information go without a challenge?

 

Exactly how many times have you used Flintcoat? I suspect I know the answer.

 

Recommending the product you specified because it can be applied to a wet surface makes little difference to both the products I mentioned since they are water based. Though I would not actually use them in the rain.

[gejohesch]

On 12/1/2022 at 1:27 PM, HighPriority said:

Most typical waterproofing membranes act a bit like a pool liner, you apply (usually paint) them onto the inside of a vessel (tank, shower wall/floor, pond etc) and the water rests against it and is contained.

If however the waterproof membrane is on the outside of the structure the water seeps through and literally pushes the membrane off the surface as they are just a thick, rubbery paint.

The negative hydrostatic membranes are usually a modified epoxy that makes a better bond to/into the substrate enabling it to withstand the water trying to push it off.

 

As to being able to fill voids in the wall by making multiple passes it really depends on the size of the voids.

In a shower situation you would flush the imperfections with silicone (or cement mortar) and apply membrane over that, small imperfections you could “load up” your brush and fill, but they often open up again on the first/second coats.

To fill poorly mortared block joints with membrane only in a situation where you were forced to only use a paint roller to apply would be a pretty tough ask.

IMHO I’d go with the WPM 300 on the inside of the wall as my preferred coating, but a guttering would beat everything.

Good explanations, I think I understood nearly everything. Quite a good summary, really, if I put it together with the comments from others that followed. It's still a bit hazy to me right now, but I think that if I print the whole discussion down and highlight the relevant bits and pieces - including the countering arguments - I will eventually be able to go to Home Pro, Global House or Watsadu, expose the problem sensibly, get the appropriate products and get down to doing the job.

 

Of course, if I was in a more "civilised" part of the country, I would just get a skilled worker to do it, but here I am in the sticks....

 

At the end of the day, I may not end up with the "perfect" wall, but I'm confident I can significantly improve the problematic wall.

 

Thanks a lot to all!

[HighPriority]

22 hours ago, gejohesch said:

Good explanations, I think I understood nearly everything. Quite a good summary, really, if I put it together with the comments from others that followed. It's still a bit hazy to me right now, but I think that if I print the whole discussion down and highlight the relevant bits and pieces - including the countering arguments - I will eventually be able to go to Home Pro, Global House or Watsadu, expose the problem sensibly, get the appropriate products and get down to doing the job.

 

Of course, if I was in a more "civilised" part of the country, I would just get a skilled worker to do it, but here I am in the sticks....

 

At the end of the day, I may not end up with the "perfect" wall, but I'm confident I can significantly improve the problematic wall.

 

Thanks a lot to all!

Personally, I’d still prefer the guttering method, but appreciate that it may be hard to work with your neighbour.

Good luck ????????

[HighPriority]

On 12/2/2022 at 11:43 PM, sometimewoodworker said:

As I have actually used the product I suggested, along with the MrFixIt version I am well aware of how to use it and what it will actually do. So no the mortar joints will not prove a problem and filling them is unlikely to be needed.

 

Why is that? Is it because when I actually know exactly what I am talking about, have used the products and know their weaknesses I don’t let incorrect information go without a challenge?

 

Exactly how many times have you used Flintcoat? I suspect I know the answer.

 

Recommending the product you specified because it can be applied to a wet surface makes little difference to both the products I mentioned since they are water based. Though I would not actually use them in the rain.

One more time, just for those with an inflated opinion of themselves and their opinion…

Youve used “MrFixit” product, maybe twice… great for you ????????
And “Flintcoat” !!
WOW, you are awesome. 
 

Why don’t you tell me how many 20kg drums of “Ardex WPM155” you’ve used ?

I have used HUNDREDS, and counting its predecessors it would be one thousand plus 20kg units over my career.
I an an active professional ceramic tiler of 40 years, my then state based waterproofing licence was number 016.

The product I recommended as my second choice solution to the OP’s problem “Ardex WPM300” is a product I’ve only used once, as in my line of work it’s a specialty product. 
I’ve read many of your posts and on many subjects you are very knowledgeable but I dislike your self presumed superiority to everyone else.

Have a nice day ????????

[thaibeachlovers]

On 11/28/2022 at 9:36 PM, Cake Monster said:

Get the outside wall rendered over correctly, and when fully dry paint inside and out with a silicon sealant paint such as " Thompsons Waterseal "

The Waterseal is a UK product, but I am sure there will be an equivalent in Thailand.

 Did you miss "the wall in question was built (regrettably) too close to another wall and it is not possible to get into the space in between (it’s only 20 cm wide). "?

 

Is there a company that does expanded foam insulation in the OP's area? Fill the space and seal the top.

OR, get a ready mix truck of cement in and fill the space ( with neighbour's consent ).

[thaibeachlovers]

On 11/30/2022 at 2:49 AM, chickenslegs said:

Is the "other wall" a neighbouring house, or a just a garden wall?

If it's a garden wall (usually a concrete frame filled with blocks and rendered) AND if you have a cooperative neighbour, you could take out the blocks then properly render and waterproof your wall.

Rebuilding the garden wall afterwards should not be too expensive.

Before I got to that stage I'd try spraying a silicone sealer on the wall ( using a long extension ). If that didn't work then try something more drastic.

 

However, even before that I'd at least seal the inside wall with something waterproof.

[sometimewoodworker]

2 hours ago, HighPriority said:

I dislike your self presumed superiority to everyone else

I have never claim to be superior. I write on subjects where I have knowledge. Your perception of my writing is yours. I certainly have no control over it.

You do have one influence on me so “Plonk”

[gejohesch]

11 hours ago, HighPriority said:

Personally, I’d still prefer the guttering method, but appreciate that it may be hard to work with your neighbour.

Good luck ????????

I will still try o get a gutter put in. I did not exclude it! But the best is to combine with some repair on the wall itself, I think.

[gejohesch]

16 hours ago, gejohesch said:

I will still try o get a gutter put in. I did not exclude it! But the best is to combine with some repair on the wall itself, I think.

One more thing - I hope I'm not abusing your patience! Maybe I have not mentioned that the room on the inside of the problematic wall is a bathroom. It's tiled halfway up to 1m60, and the tiles have not shown the dampness I have been talking about. It's only the wall higher up that gets damp. I can think of 2 reasons for that:

1) the water falls from the roof and only (mainly) penetrates the wall just below the roof, say over the upper 0.9m of the wall.

2) The mortar used for tiling added up an extra layer of insulation to the wall.

 

Or maybe it's a combination of the 2!

 

In any case, as the paint got ruined to a degree by the dampness, the wall needs some minor repair on the inside. Instead of painting again I was thinking of tiling the wall all the way to the ceiling. I think I can do that myself (I have done just a bit of tiling in a friend's place), back buttering the tiles with mortar (not just putting mortar on the wall) to make sure there is no gap between the wall and the tiles.

 

I know some of you are professional tilers, so there could be so further advice on this tiling idea?

[sometimewoodworker]

2 hours ago, gejohesch said:

In any case, as the paint got ruined to a degree by the dampness, the wall needs some minor repair on the inside. Instead of painting again I was thinking of tiling the wall all the way to the ceiling. I think I can do that myself (I have done just a bit of tiling in a friend's place), back buttering the tiles with mortar (not just putting mortar on the wall) to make sure there is no gap between the wall and the tiles.

That will probably work. I strongly suggest using waterproof tile adhesive and ensure that the full surface is covered.

 

as long as you get good adhesion to the wall it probably won’t fail and will be the easiest job and if it does fail then you have enough suggestions to work from