How to fix moisture issues in garage walls?

[shezere]

For visual effect, I have decided to board over the bottom half on my paint damaged garage internal wall with shiplap. We have had damp problems moreso on one side of the garage, as pictured on the rendered wall. I am thinking the moisture is coming from outside, where we have approx 3mts concrete path with steps to a metre high, with expansion tape installed alongside the house. When it rains heavily, I am guessing the water is entering via the gap below the expansion tape?  I only thought about the outside recently, and am wondering if the above sounds logical? Could the rain saturate the ground under the expansion tape, creating moisture on the internal single brick rendered walls? Apparently, all was waterproofed when the house was built, but who knows? Question 1. If I were to use expanding silicone, and put the expansion tape back in if possible, would this create enough barrier to prevent water coming into the garage (if my guess is correct)? Its a single brick, rendered wall. Our home is built utilising the natural slope of the land wherever possible using steps. Some parts of the wall externally, have the pathway and steps around 11/2 mt plus higher than the garage floor, and down to almost around 20cm as the level changes in other sections. Where most of the moisture has come in, coincides with the height of the section outside from what I can see. For the most part, I am guessing the water saturates the ground and finds the exit point and saturates the bricks? The damp areas tends to start at the ground level, and some areas have crept up the wall in other sections. We have recently epoxied the floor, including 100mls up the wall, hoping to create a moisture barrier inside the garage where the concrete meets the walls. I guess this is the easiest point of water causing damage .. where the wall meets the concrete. We now have the preexisting issue of the flaking paint and/or fluorescence on the rendered wall. Question 2. If I remove all the flaking or damaged paint  (but not all the paint on the wall) and treat with a moisture product in the affected areas, install flexible silicone outside, will this help my problem? The shiplap will be attached to timber framework, with a 3cm gap around the whole base, so air can circulate? Question 3. Do I use a sander or grinder to remove the flaking, damaged paint? If so, what grit do I purchase to do the wall?  Is removing all the paint from the walls necessary, or can I do the affected areas only? The height of the shiplap will be 1.5m height with a negative damp product (was recommended, Crommelins DampStop), so hoping someone can help answering my questions before I go to a lot of trouble?  Thankyou.floor level.1200 height up the wall.  

[EricL]

Hello @shezere 

Yes, that is the tool you can use to strip the paint off your wall. The Josco 100mm Twistknot Bevel Brush will require a grinder in order for you to use it. Please remember to wear personal protection such as gloves, goggles and a mask while grinding the paint off as it will create quite a mess. Please note that the silicone sealer I suggested is to be used outside between your wall and pathway.

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Afternoon @shezere 

To answer your two questions 

Q1 - Also, Dave-1, the external wall is in tact, so do you mean to paint a damp product along the base of the wall, near the path edges for hydrostaic? pressure? The actual wall is east facing and we have around 50cm eaves.. but the path of course gets rainwater on it which I am hoping is the cause of the problem. 

A1 - Hydrostatic pressure is water pushing through material from the other side. So if you look at that wall with a poer point on it, it seems that there is 1m of your wall in height that is affected.  With the damp product it is usually painted/installed on the soil side before its back filled. What I was refering to is a product that can be applied to the front (It has to be able to withstand that push of water through the brickwork (yes its porus) and not push the product off the wall) I have a faint memory that within the facebook adds I saw a product but cant find it atm 😕 

Q2 - Oh, and Dave. love the idea of slatted wall in preference to covering the whole wall. Can make it the fanciest garage around.. took this pic off Facebook and turned it around... Maybe not with so much deviated lengths, but still can get quite artistic. guessing you mean similar, with gaps between each slat... 

A2 - I am considering part of my foyer to do the same. The reason I suggested the slats and definently the air gap was to mask the effervescence of the water wanting to push the paint off the wall. This would be an easier tho not best option to fix the issue. (Best is dig up outside :/). At the same time to provide as good a surface as possible to allow it to air dry. Like you said it could look very artistic, I say modern and stylish

Dave

[shezere]

I seem to be getting a tad confused here.. response to last message.

1. The wall with the water damage is 'inside' the garage.. the wall 'outside' is a lot higher than the wall inside (hence the damage shown about 1mtr up the wall on the inside). I cannot dig anywhere along the wall outside.. there is a concrete pathway along the whole wall (with soil beneath the path), so anything I do other than use caulk has to be done to the inside wall. There approx 1cm of gap with expansion tape between the exterior wall and the pathway on both the wall and fence structure (both brick).. So for outside, I need to know if I put the caulk over the tape or remove the tape, put in the caulking and then replace the tape, or once the caulking is installed, does that now become something similar to the expansion tape?    

2. Definately will do slats.

[Dave-1]

Good Evening @shezere 

I will try and cller up the confusion.

Because you cannot dig (or it would be incredibly costly) is why I suggested the slats as a cover/mask. I was pointing out where the problem is coming from and how to disguise it/work with it. I will keep an eye out in facebook land to see if a waterproof product comes across my newsfeed that could be used.

The edge down the side of the house could be allowing water under the concrete and then it exiting via the effervescence on the wall. The expansion tape/material is more for the concrete expansion when the concrete is hot or cold then  for waterproofing. You could try sealing as you suggested it but I wouldnt be confident it will last. If there is a noticable air gap anywhere along the path then yes I would seal the air gap. The water could be coming from the top of the path or elsewhere (not directly above the effervescence)

I would not try to pull out the expansion foam and replace it. The concrete has formed around it and it will be a painfull exercise to remove let alone managing to put new expansion foam back down.

Dave

[EricL]

Hello @shezere 

My apologies, I did not mean to cause any confusion. The repair I was suggesting is for the outside of your wall. I suspect that water was entering your wall through the gap of your pathway and the wall outside. By covering this gap with silicone, you reduce the possible number of ways water is entering through your wall. No digging is necessary, you only need to clean the gap as best as you can before you apply silicone. I hope this clears up the confusion.

I agree with Dave-1's assessment, please do not remove the expansion tape inside the wall.

Eric

[Nailbag]

Hi @shezere 

By the looks of the supplied photos the internal living space are quite deep to the external ground. If this space was always part of the original build and not an extension, then I would agree with your observation as to why at the least the external walls wasn't double brick?

With all due respect to my colleagues I think your scenario may be beyond long term solution advice from an online source. Personally, I would be engaging the services of a local "Domestic Building Engineering" company to evaluate. Since the initial build was back in 2008, there since may have been additional aspects added to the property not factored in the original plans regarding waterproofing the sub-level spaces. Though they may not be able to provide a solutions path, they should be able to direct you to a service that is. Once satisfied the water ingress is resolved you are safe to build the internal slatted wall feature.

Nailbag

[shezere]

Thankyou @Dave-1and @EricL .. So i use the sealer on top of the expansion tape?

[MitchellMc]

Hi @shezere,

To seal the expansion gap, I suggest cutting the top 10mm of it away from the surface to create a trench. I'd recommend using Sikaflex 11FC, which is the appropriate product for expansion gaps. Ensure it fills the trench and contacts both the wall and the steps with no gaps. You can use a wet finger to smooth the sealant.

Apart from water entering at the expansion gap, it could be entering from under the stairs from groundwater. As @Nailbag mentioned, a more thorough investigation by a professional is likely warranted.

Please let me know if you have any questions.

Mitchell