Fix exterior hole in stucco wall

[sundancemcc]

Hi, I was wondering what the correct way to patch a hole in the wall left by a wall mounted AC unit? The outside is stucco and inside drywall.

[HayZee518]

a/c

what does the hole look like? are you right down to the sheathing or is there a scratch coat of cement?

[sundancemcc]

The hole is 25x15 inches and is currently open from the inside to the outside. I can fix the inside part myself ok but don't know how to go about doing the stucco part. Like if it needs a board backing, if it should just be the stucco paper and wire or whatnot. Also if I should install the drywall patch first then stucco or vice versa. Is there a best type of stucco to use?

[HayZee518]

stucco

Go to this url site. It explains the different types of walls and how to apply the base coat and finish.
How to Apply Stucco | DoItYourself.com

[pushkins]

and remember that once you put the sheathing back in the hole you MUST run a layer of felt paper before the mesh, I often see the felt paper left out and this can/will lead to a huge issue with moisture if it's not done.

[sundancemcc]

I looked around the hole after breaking it out about an inch and it looks like it's just stucco/wire/paper directly next to the frame and insulation. I tried just putting the paper and wire up and trying to stucco on that but it keeps pushing the paper in at spots. Should I put up the drywall and insulation in the wall first to give it a little something to push against?

[pushkins]

No it should be towards the exterior in this order>>>>> stud.....osb/sheathing.........vapor barrier (felt paper)........mesh.......stucco It's the osb/sheathing that stops the portland cement product (stucco) pushing into the house.

[sundancemcc]

Some more info I just found out is that this house was built in the 60's and the now bedroom used to be a garage. I looked further down the wall, from the inside in between the wall and I don't see any sheeting. If I put some sheeting up on the studs the new felt paper won't be able to under lap the existing.

[HayZee518]

stucco

then whomever applied the stucco didn't know the proper layers to build on to apply the stucco.
your merely patching the hole won't satisfy the problem of moisture getting under the existing stucco.
to do it correctly, I'm afraid you'll need to remove a good portion of the stucco and see where there is any sheathing and build up from there. your building inspector didn't do as very good job. I think pushkins will back me up on this.

[sundancemcc]

Ok, thank you very much. It's not the first odd thing we've found here.

[pushkins]

So the stucco is on the mesh and the mesh is on felt paper that is all nailed to the studs ? If so that is a very poor stucco job with a very high probability of moisture mitigation.

How much room is between the stud face and the existing stucco ?

[sundancemcc]

There's not any space. I'm took an image the best I can. You can see the old felt paper is nailed directly to the stud.

[pushkins]

Okay your going to have little option but to duplicate what the original contractors did, use a couple of layers of 15lb roofing felt (30 would be better), then add your mesh
, might be easier to use the mesh they sell in Lowe's or H.D that is for older bathrooms (and stucco) where they used it for the cement layers before tiling, it is much more rigid and will allow Portland stucco to stick and hold. Make sure the mesh is behind the existing stucco an inch or two as much as possible, this will help any possible future cracks in the repair to existing stucco seam.
It would also be a good idea to apply "Bondcrete" (available in the concrete section of all big box stores) apply it to the old stucco raw edge, it will also help in the seam bond.
Finally you will want the repair to slightly overlap the existing and tapper away, kinda like dry walling a seam, it does not need to be much just a way of feathering out the repair.

Here's a useful video >>> How To Repair Stucco - YouTube

[sundancemcc]

Thank you and thanks for the video as well.