Can I put siding over painted brick?
Josty_Sieverding
| Posted in General Questions on
Hello all,
Long time lurker first time poster haha.
I have a best practice question.
Context:
Feel free to skip this if you just want the question below.
One of my friends lives in an old house that had brick and plaster wall assemblies. Before they bought it someone did an “upgrade” so now the assembly varies throughout with exposed brick in some place, furred out walls with drywall in others and I think even drywall laminated over plaster on the ground floor. The brick was also completely painted from the outside in a dark color.
The issue he is having is that the paint is failing on the exterior due to trapped moisture and because of this the brick has also become extremely brittle. I can poke holes into the brick with my finger in some places and there’s spaulding all over. This problem has also been exacerbated by poor flashing details at the top of the assembly that have dumped even more water into the brick.
I am trying to advise him on the best steps from here and have two options. Please correct any wrong assumptions or propose alternate methods if there is something more cost effective.
1. In order to properly correct the issue without compromising the homes appearance I think he needs to scrape or blast the paint of the brick, have a mason tuckpoint and repair all defects and then apply a vapor open water repellent. My biggest concerns with this approach are cost and the condition of the brick. I think if the brick were sandblasted he would likely have to make even more repairs to the point of practically touching the entire wall because so many faces will likely come off in the process. He could attempt to scrape the paint of gently but I think that is going to be cost prohibitive and might not solve the issue.
2. This goes against everything I stand for haha but the alternative would be to cover the brick with siding. I think he is likely going to save more money on this option because there are more qualified contractors in our area that can do this work. I would assume he still needs to get the paint off but could afterwards only repair the structurally unsound areas as opposed to also repairing all the aesthetic defects. My questions around this approach are how would the brick need to be treated before covering it? Can we use a peel and stick WRB that’s vapor open? Can he just leave the raw brick? Would a dimple mat alone suffice under the siding? Please enlighten me as this is the one portion of the assembly I am unsure of. I think allowing it to dry to the outside is important given the various conditions on the interior.
Question:
Can I install siding over painted brick? My assumption is not, so if that’s true how do I need to treat the brick masonry prior to covering it up.
Thanks for all your help!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Cart before the horse.
You described bulk water issues and vapor diffusion issues that are causing structural damage. These problems need to be addressed before the brick is concealed; repointing won’t do anything to help.
Further, you’re conjecturing in areas where you shouldn’t. Dressing the brick back up could be less expensive than siding the building (again, structural repairs either way), but you won’t know until you consult with appropriate subs. Siding isn’t as simple as you think- this will get into the windows, doors, cornices, and any penetrations.
Possible, even, that the paint is causing the brick to decay as it likely isn’t vapor open (enough).
Also- this is a brick house. Concealing the brick, and attempting to conceal problems, will only create more problems. I say, leave the brick as brick. If your friend does not like the appearance, or doesn’t have the budget or stomach for extensive repair, it’s time to move to a different home.
Climbing_carpenter
Good catch I should have mentioned that in my post. He's had a more qualified roofer come through and redo the flashing issues that were causing the bulk water penetration. The main problem at this point truly is just the brick face.
As you mentioned I do believe the paint is not vapor open and is the root cause of the deterioration. We had really sever wind with driving rain and just that was able to fully flush out some of the brick faces because they are so brittle.
Based on your comment then would your recommendation be to remove the paint and go from there with brick repairs. And make the call on whether or not to proceed with siding after that work has been reviewed and completed by a qualified mason?
The above questions are very important. Depending on where the moisture is coming from, siding won't fix the issue. For example I have around me a two story painted brick. The paint is peeling on 2nd floor above the windows, so in that case the moisture is coming from air leaks on the inside.
Fixing air leaks on the inside sounds simple but typically end up being very disruptive if it is something like a balloon framed house with brick veneer.
If the brick is damaged from rain exposure (zero/small overhangs), siding over it will protect the brick. In most other situations, the siding won't make the situation better or worse*.
If the moisture is from the inside, you can still fix it from the outside with exterior rigid or EIFS. The goal here is to add enough exterior rigid so that the brick is kept above condensation temperature so moisture will not accumulate. In most climates this is not all that much rigid as long as there is no/minimal fluffy on the inside. This still requires very careful detailing of rough openings as any bulk water leaks will no way of drying through the exterior rigid.
My $0.02. Fix the water leaks, tuckpoint as needed and touch up with a permeable paint. If it still continues to peel and spall, go for the exterior rigid.
*assuming rough opening details are done right, you don't want the siding to push more bulk water into the brick.
Akos,
Thank you for the advice. Do you have a preferred permeable exterior grade paint that you can recommend?
Thanks,
Generally anything water based that doesn't specifically say it is a vapor barrier. Some manufacturers publish PERM values (or at least say something like "highly permeable") for their outdoor paints but you'll have to do some digging to find it.
If the existing paint is oil based (quick check if it dissolves with acetone->water based, if it dissolves with paint thinner -> oil based), you'll need a primer before putting on the new paint where they will overlap.
Great thank you!