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.  

[JacobZ]

Hi @shezere,

A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us.

In order to get a better understanding of the project, can I ask for some photos of the outside of this wall showing where you believe the water is entering?

Waterproofing is a complex task that can be tricky to achieve even with all the right products, as water will always find a path of least resistance. I think we should try to address this issue fully before moving on to anything else, as any efforts to conceal the water damage on the inside will be wasted if the water is not kept outside.

Unfortunately, it would be impossible for me to answer your first question without seeing the outside of the property, so once I can see it, I will try to answer more thoroughly.

Once I can see the outside of the property, I will assist further with the other questions as the best approach will be governed by what is on the outside. 

Allow me to tag @Nailbag, @Dave-1 and @Jewelleryrescue for their thoughts.

Jacob

[Dave-1]

Good Afternoon @shezere 

Getting the moisture issue fixed is the first step. Otherwise you will be wasting money installing the shiplap over the surface I am afreaid. 

Will wait for some more photos of the area along where you think the water is entering. I have had water enter my garage and also under the house. Both lots of water appeared to be subsurface water from when it rained intensley. I ended up removing the soil from the single thickness of brick wall of the garage and problem solved. Lots of effort retro fitting the area by removing the soil but probarly something you need to keep in mind. 

There is nothing I know that you can put on the outside surface of a brick/concrete wall that will stop the hyrdostatic pressure of water trying to push through. 

I was surpprised the pathways and the amount of subsurface water that travels under the concrete path.

Dave

[shezere]

I have done the best I can for the photos.. the slope is quite strong.. the pathway is longer than I originally said. There is also gap in bricks on the steps that could be causing problems too.. thx everyone..gaps in bricks could also add to the issue?? I guess. gap has tape between wall and path on both house and fence side.path has a long decline to about 2mtrs from the top to the bottom of steps.Garage ceiling is around 1.2mtrs above the path at the top, and full height at the bottom of the steps.. can park a caravan in the garage.no idea what the tramlines are from.. pic is at the top of the pathway.this is the doorway into the garage. There is a gap between both surfaces.this is at the base of the internal wall, where the gap from previous pic is aligned.. plus gaps in steps?

[shezere]

thanks Dave, have posted some more pictures from outside.. . Due to renovating the garage, there is a lot of stuff that is not normally present in the photos.. 

[EricL]

Hello @shezere 

Thank you for sharing those extra photos of your wall. It's possible that water is entering the gap between your pathway and the wall. There is also the possibility that water is passing through under your concrete steps and meeting up with your wall. The only other source of water is from your roof where a leak might be occurring and is bridging along your brick wall. 

It is difficult to tell where the water is coming from exactly, but you can try to eliminate some of the possible entry points that might stop or lessen the amount of water coming through. I recommend cleaning the gap between your steps and the wall on both sides. I propose sealing both sides of the path just to be on the safe side. I suggest using Sika 310ml Grey Concrete Sikaflex Pro+ Polyurethane Sealant. My best advice is to make sure that the surface of both the path and wall be clean and free of debris before you apply the sealer.

In regards to removing the paint on the wall, you can use sandpaper, but I suggest looking at the Josco 100mm Twistknot Bevel Brush to completely strip the paint off the wall. Please remember to wear personal protection such as gloves, goggles and a mask when using the grinder. 

Let me tag @JacobZ just in case he has anything else to add.

If you have any other questions we can help with, please let us know.

Eric

[Dave-1]

Good Evening @shezere 

Thank you for the photos, Not a lot of spaces for water to really gain access in the quantities id expect. I would be following the steps @EricL has suggested and see if it changes the amount of issue with the interior wall. I would hold off a little if you can and see next few times when it rains. The only other way I can imagine is that subsurface water traveling along under the concrete path and impacting your wall and then threading through it. 

I would be tempted to contact a waterproofing specialist if the wall stays damp after your sealing the outside points. There may be something they have up their sleeves I hope If there is please let us know as it would be something to add to the box of tricks.

Dave

[shezere]

Hi Eric, Dave and JacobZ,

thankyou for your advice and recommendations regarding what product to use outside the wall area. I will get organised asap.

We have a Colourbond roof, and commercial guttering. Also have a loft in the garage.  I had the roof and downpipes checked last year, and all the screws changed on the roof as a maintenance plan. I read that they should be changed approx every 10 to 12 years. We get almost zero debris in the guttering. So I dont believe the roof is an issue, but I can get that checked again, to be sure.

And then I begin stripping as much flaked or damaged paint from the internal wall. Would you also recommend I use a crommelin dampstop product on the wall, which was recommended to me by someone I spoke to in regard to what to use for damp proofing. 

As for the amount of water that has penetrated, this has been happening for a long time. I spoke to the builder about it when I first noticed the paint changing, which was possibly in 2011.. he advised me at the time, that there would be no damage to the structural integrity of the building, and its to be expected when there is soil higher outside than the floor inside? I suggested at that point, then perhaps the wall should have been double brick.. he said 'not on the plans'. Tend to fight losing battles with builders it seems.  The house was built in 2008. So my guess is it has been happening since then.

thankyou again.

Sheryl 

[Dave-1]

Morning @shezere 

I am trying to remember a product that I saw in Facebook land once that said it could be installed on the outside of a wall with hyrdrostaic pressure on it. I thought I had liked the page but for the life of me I cannot find it. I had put it into the same range as making gold from lead tho so thats probarlly why I dont remember it If you do find a product you want to use please let us know so if someone else has the same issue we can suggest.

That said, there is always a "that said" Id be tempted to remove the flaking paint back to bare surface and keep the wall ventilated for a period. I dont think I would be covering the wall up mostly as you wont see the condition of it if it deteriorates more. Maybe An open vertical slat wall covering, that way you will have air circulating and also a covering effect so you wont see the effervescence. (two or three rails installed horizontaly on the wall with 40mm ish slats standing vertically and spaced 20mm apart type deal. )

Dave

[shezere]

hi again everyone,  thx for all the help to date. I am off to Bunnings shortly, so will grab the silicone as recommended to begin doing the side of the pathway (do I have to remove the expansion tape and reinstall)? I just wanted to check, if this product number from the Bunnings website, is what EricL is referring to in regard to the beval brush.  I/N: 6326672. Just checking, this will remove most of the paint on the wall, which is probably preferable if I am going to apply a damp product? 

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. 

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...  taken off fb.. and turned around.

Thanks again guys.