Advice on carpeting an old garage - how to prep old concrete?

Forums › Home Workshop DIY › Advice on carpeting an old garage - how to prep old concrete?

jonathan18

7413 posts

Uber Geek

ID Verified

Trusted

#296398 14-Jun-2022 09:30

We’re tidying up our old very original garage, with the last big job being replacing the garage carpet the previous owners installed. The problem is the concrete is well and truly ‘original’: it’s not only uneven but also clearly has an issue with rising dampness (see photos below).

The next problem is that the first quote we’ve had back is for over $3k, given not only do they need to grind and feather the concrete, but also apply something called Uzin PE460.

We don’t think it’s worth spending that much, given the age/use of the garage, but would still like to improve it to the point we can replace the carpet ourselves (noting the current carpet is not fixed, we’d probably do the same). So I’d really appreciate some advice on a few key things:

1. What is a cost-effective way to deal with the dampness? Our builder has recommended Sika Blackseal Plus, which is a brush/roll-on waterproof membrane - will this work ok? Other products you would recommend? It doesn’t need to be perfect, but just a decent amount better than it is now.

2. We’re not planning on getting it ground, given we’re not going to be gluing the carpet down; rather, we plan to scrub and clean it before applying any seal. Will that be adequate?

3. What’s the best way to reduce water ingress and protect the carpet at the entrance? (This is where it’s worn the most, both as a result of it’s where the car tyres first make contact and being closest to the door.)

Thanks for any tips and advice.

1 | 2 | 3

649 posts

Ultimate Geek

Lifetime subscriber

#2926323 14-Jun-2022 09:57

Not sure about the products you have quoted, but it is definitely worth looking at improving drainage around the garage if at all possible, before you even attack the concrete. If the ground under it is constantly wet then you'll be fighting a losing battle, not to mention that most products will adhere far better to clean, dry concrete than even slightly damp.

geoffwnz

1587 posts

Uber Geek

ID Verified

#2926360 14-Jun-2022 11:17

I have similar age concrete in my garage.

I solved the water ingress at the doors by gluing and dynabolting a strip of decking timber in behind the door. Low enough that driving over it is no issue and tall enough that it prevents water blowing under the door.

It does need lifting and resealing under it after a number of years of use but definitely stopped the lakes forming inside.

MotorDrive Rallying

blackjack17

1705 posts

Uber Geek

#2926372 14-Jun-2022 12:00

jonathan18:

1. What is a cost-effective way to deal with the dampness? Our builder has recommended Sika Blackseal Plus, which is a brush/roll-on waterproof membrane - will this work ok? Other products you would recommend? It doesn’t need to be perfect, but just a decent amount better than it is now.

This will not work.

Bitumen sealants will only work on the positive side of hydrostatic pressure (i.e. the wetside) they don't grab on enough to stop the water coming through.

For the cracks you might need something like this and for the surface something like this

https://www.bunnings.co.nz/sika-4l-damp-stop_p0138036 or https://www.bunnings.co.nz/cemix-4kg-crystal-proof_p0142103?store=9518&gclid=Cj0KCQjwwJuVBhCAARIsAOPwGASS2RibxaXoXbj4d169kPYd7v2EzX7a5nXy-DIT8mxJvq4WJYd21hwaAg9cEALw_wcB&gclsrc=aw.ds

It might pay to give the concrete an acid wash first.

Negative pressure water issues are an on going battle. Water will always find a way.

Electric kiwi signup credit Sharesies credit

mdf

3512 posts

Uber Geek

Trusted

#2926416 14-Jun-2022 12:40

Do you know if the concrete has been sealed or had anything applied to it previously? Best test is to spill a few drops of water on it and see if they immediately soak in or bead a bit on the surface. Primers and steps will vary a lot depending on what is already there (if anything).

This is a pretty comprehensive resource: https://www.resene.co.nz/archspec/datasheets/SIPDS-No-3-Concrete.pdf

tweake

2391 posts

Uber Geek

#2926423 14-Jun-2022 12:54

jonathan18:

The next problem is that the first quote we’ve had back is for over $3k, given not only do they need to grind and feather the concrete, but also apply something called Uzin PE460.

1. What is a cost-effective way to deal with the dampness? Our builder has recommended Sika Blackseal Plus, which is a brush/roll-on waterproof membrane - will this work ok? Other products you would recommend? It doesn’t need to be perfect, but just a decent amount better than it is now.

2. We’re not planning on getting it ground, given we’re not going to be gluing the carpet down; rather, we plan to scrub and clean it before applying any seal. Will that be adequate?

3. What’s the best way to reduce water ingress and protect the carpet at the entrance? (This is where it’s worn the most, both as a result of it’s where the car tyres first make contact and being closest to the door.)

Thanks for any tips and advice.

as already mentioned the black seal won't work.

the uzin pe460 is an epoxy coating. frankly 3k for grind and epoxy coating is cheap.

something like cmix crystal might work, its a concrete sealer.

first thing i would do is rip out the carpet , let it dry a bit, then do the plastic bag test and see how much of it is moisture coming up through the concrete or just water blown under the door. if it does have moisture coming through the concrete then you need to sort out a ventilation setup and preferably something to keep the air moving (ie ceiling fan).

obviously fixing the doors so they seal at the bottom is a priority. the big doors should seal below the top of the concrete.

Bung

6477 posts

Uber Geek

Subscriber

#2926432 14-Jun-2022 13:07

If it's an old garage the concrete floor is unlikely to have any plastic under it but a wet car will drip a lot of water and if you've got AC there will also be the condenser drain. You need a carpet that can get wet.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#2926437 14-Jun-2022 13:21

on my new garage floor i used a 2 part epoxy, and looking into the instructions it said "If the concrete substrate has a rising dampness issue, apply a primer coat of Epotread Moistureseal"

so maybe give Regis Coatings a call and see what they recommend as they dont list Epotread Moistureseal now.

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

elpenguino

3419 posts

Uber Geek

#2926458 14-Jun-2022 14:17

pih: Not sure about the products you have quoted, but it is definitely worth looking at improving drainage around the garage if at all possible, before you even attack the concrete. If the ground under it is constantly wet then you'll be fighting a losing battle, not to mention that most products will adhere far better to clean, dry concrete than even slightly damp.

This.

You can't easily amend how the floor was laid but you can decrease how water attacks it by giving it an easier path (i.e. reduce the hydrostatic pressure under the floor).

Typical remedy is a trench dug around the foundation, down to the level of the footer. An envelope of geotextile is filled with 20mm chip and a perforated drainage tube leading water away to be dealt with.

Even if you were to replace your floor (how deep are those cracks?) you should still consider exterior drainage.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

jonathan18

7413 posts

Uber Geek

ID Verified

Trusted

#2926468 14-Jun-2022 14:40

Thanks, all, for the really useful responses. Great to have a bunch of things clarified, eg unsuitability of the product recommended by our builder!

I’ve taken on board the comments re trying to address the source of the problem, and a colleague (ex builder) has offered to take a look to advise how we could improve drainage etc. The problem is the garage is built on the back corner boundary of the section, which makes it a bit more difficult to mitigate water ingress from those two sides; and there’s concrete (driveway and a path) right up against the other two sides…

(My colleague also pointed out that even if we successfully stop the water rising through the top of the concrete (without addressing its ingress), it’ll still look for a way out - and that’s likely to be the up the walls of the garage!)

Thanks also for the recommendations of products that can potentially be applied; I imagine I’ll still need to look at some form of sealant, even if we do manage improve the water problem (ie, I doubt we’ll be able to solve it completely, given the limitations of the site), so I’ll do a bit more digging into this as well.

Based on what’s been noted in other posts, I think there’s also an issue with the (lack of?) sealing of the roller door, so will also look more into this - may post a photo of that and seek advice on how best to manage it.

tweake

2391 posts

Uber Geek

#2926478 14-Jun-2022 15:25

pih: Not sure about the products you have quoted, but it is definitely worth looking at improving drainage around the garage if at all possible, before you even attack the concrete. If the ground under it is constantly wet then you'll be fighting a losing battle, not to mention that most products will adhere far better to clean, dry concrete than even slightly damp.

thats actually an impossibility.

you always need good drainage and ground should be sloped away from the building. but it only deals with bulk water, not moisture.

you cannot get "dry ground". moisture moves through materials from a wet area to a dry area, which makes it wet again. ie if you make it dry moisture moves from the rest of the ground to that spot and makes it wet again. drainage will never make the ground around it moisture free. this is why we have to have moisture barriers under the concrete. something they figured out pre 1900's.

elpenguino

3419 posts

Uber Geek

#2926490 14-Jun-2022 15:52

That's an interesting point. The thing is that, if there was no membrane fitted under the floor, it is very difficult to fit one now.

I recently watched this video about groundwater.

https://youtu.be/bY1E2IkvQ3k

As far as remedial actions to be performed now, improving the drainage around the building will reduce the groundwater pressure gradient and reduce the ingress of water into the floor. But it only reduces the pressure, it does not stop it, which is where your under floor membrane comes into play. Ideally both forms of protection work together.

All of this is for nought if the driveway slopes into the garage and water gushes in when it rains :-) so any problem there should be addressed first.

Installing the drains I mentioned would call for breaking up paths and other surfaces which abut the garage. This is all work and expense, but as they say, if you want it done right .........

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

lxsw20

3552 posts

Uber Geek

Subscriber

#2926507 14-Jun-2022 16:58

If the carpet is just to tidy things up a bit, you might be better with something like a grey astroturf, that way it's not going to rot/smell when it gets wet.

https://www.mitre10.co.nz/shop/fortify-artificial-grass-w-2m-h-7mm-grey/p/367116

mattwnz

20141 posts

Uber Geek

#2926537 14-Jun-2022 18:00

What about using rubber gym mat flooring tiles ? https://www.leewarehouse.co.nz/products/gym-flooring-tile-two-size ? That rising damp doesn't look good.

tweake

2391 posts

Uber Geek

#2926561 14-Jun-2022 19:40

one of the problems of putting matting down is all the moisture will either be soaked into it, or it will form on the underside and you end up with wet floors.

probably better to not have flooring and increase the ventilation and air movement to evaporate the moisture.

jonathan18

7413 posts

Uber Geek

ID Verified

Trusted

#2927696 15-Jun-2022 09:27

So this is what the doorway to the garage looks like currently. The most obvious issue is the gap in the middle where I assume the old door was fastened or similar - what would be the best product to fill that gap? (It still has wood in there).

It’s also clear the garage floor isn’t flat, as the garage door installer hasn’t been able to get anything close to seal for a decent length on the right side (facing out). How am I best to address this, given it’s not along the full length of the seal? Thanks for any further tips!

1 | 2 | 3