[miamicuse]

I cut a small trench on my exterior stucco-ed concrete block wall to run a PVC pipe. The area is about 32" X 5" and 3" deep before I unserted the pipe and foam. Now I am trying to cover it back up.

I will be trimming back some of the foam that is sticking out too much, then I will be packing some mortar/cement above, below and behind the pipe until it is about flush with the outside of the pipe, that will take it to about 1" below the finished surface.


Then I will be securing a 4" X 32" piece of metal lath.


I will have about 3/4" to 1" of thickness to apply the stucco.


Do I need a traditional 3 layer system or can I do it all in one coat with such a small area?


Is Type S mortar acceptable as the product to use in this case?


In looking at the texture I have, I think this is called Loose Knockdown Dash?

 

[ClarenceBauer]

You do not need to use a three coat Stucco over CMU.
You can apply your scratch coat (first coat) than when it is firm (your thumb won't leave a print) you can apply the next coating & texture or float it as needed, Make sure you moisture cure it DO NOT let it just dry out.

 

[miamicuse]

You do not need to use a three coat Stucco over CMU.
You can apply your scratch coat (first coat) than when it is firm (your thumb won't leave a print) you can apply the next coating & texture or float it as needed, Make sure you moisture cure it DO NOT let it just dry out.

Thanks, If I pack mortar to fill in all the cavity behind the pipe, then attach the lath, then the stucco, will the underlying mortar around the pipe cure fine or do I need to wait a while before I attach the lath and final 1"?


Any suggestions to match the texture? I am thinking after I smooth the final coat, just fling some slightly watered down stucco on it, wait a bit then gently knock it down but no idea if that would work.

 

[ClarenceBauer]

As for attaching lath? Why are you wanting to use lath? Lath is for mechanical attachment of the Stucco.
If you are going to use lath than fold it over the pipe than pack the mortar in.
Question how close is the pipe to the finished surface of the Stucco ifg less than 5/8 inch it will mostly crack along the pipe.
As for the finish apply the stucco trowel smooth than dash on a mixture & trowel smooth. You have what is called Spanish Lace.

 

[miamicuse]

As for attaching lath? Why are you wanting to use lath? Lath is for mechanical attachment of the Stucco.
If you are going to use lath than fold it over the pipe than pack the mortar in.
Question how close is the pipe to the finished surface of the Stucco ifg less than 5/8 inch it will mostly crack along the pipe.
As for the finish apply the stucco trowel smooth than dash on a mixture & trowel smooth. You have what is called Spanish Lace.

The outermost part of the pipe is recessed about an inch from the finished surface. That's why I was thinking I would pack mortar all around the pipe until I have a flat surface of varying depths of mortar except at the middle it will be the outermost part of the pipe. I guess I was thinking if I attach lath over that it will help with the 1" of stucco over it.


I guess I could wrap lath or chicken wire or something around the pipe and just pack in mortar until about 1/8" before the finish coat, I just worry if too much depth in one application may cause it to "slump" over.

 

[ClarenceBauer]

The outermost part of the pipe is recessed about an inch from the finished surface. That's why I was thinking I would pack mortar all around the pipe until I have a flat surface of varying depths of mortar except at the middle it will be the outermost part of the pipe. I guess I was thinking if I attach lath over that it will help with the 1" of stucco over it.


I guess I could wrap lath or chicken wire or something around the pipe and just pack in mortar until about 1/8" before the finish coat, I just worry if too much depth in one application may cause it to "slump" over.

Do it in two lifts & it will be fine just make sure you moisture cure it for 72 hrs.

 

[miamicuse]

Do it in two lifts & it will be fine just make sure you moisture cure it for 72 hrs.

Thanks ClarenceBauer! So basically, pack mortar tight behind and around the pipe until flush with the outside of the pipe, let it cure for 72 hours with occasionally misting with a spray bottle. After 72 hours I can apply a scratch coat, wait till it is firm then the top coat and texture. I don't need any lath around the pipe then?

 

[ClarenceBauer]

Thanks ClarenceBauer! So basically, pack mortar tight behind and around the pipe until flush with the outside of the pipe, let it cure for 72 hours with occasionally misting with a spray bottle. After 72 hours I can apply a scratch coat, wait till it is firm then the top coat and texture. I don't need any lath around the pipe then?

@;
The above is correct you are good to go.

 

[miamicuse]

The above is correct you are good to go.

Got it thank you Clarence! :vs_cool:

 

[miamicuse]

Some final questions if I may ClarenceBauer, I am about ready to apply the scratch coat and shortly after the finishing coat/texture. I have been using Type S mortar, should I use that for the finishing coat & texture or I need something even a bit finer?



Also once I applied the finishing coat with skip trowel I need to come back to gently knock it down to try to get that spanish lace pattern, do I wait a bit (like 15-30 minutes) or do I do it right after?


Finally do I need to apply some bonding agent on the existing finished wall around the outside of the repair area so that if my trowel end up pushing some of the texture over the edge to blend in those cement won't be sitting over old paint? Or don't trowel over the line?

 

[ClarenceBauer]

The type "S" is ok if that is what you have for that small area the PSI is high it should be around 75 PSI.
For the texture you should be able to double back with in a couple of minutes.
As for bonding agent over a painted surface NO the bonding agent & Stucco will only be as good as the paint & it will fail over paint.

 

[miamicuse]

If it will fail over paint then I can't texture over the cut edges? But in order to match the textures I have to overlap a little over the edges to blend the new over the old right?

 

[ClarenceBauer]

If it will fail over paint then I can't texture over the cut edges? But in order to match the textures I have to overlap a little over the edges to blend the new over the old right?

You should chip all along the cuts to remove the existing texture look at the photo & you will see a chipped off finish just under the fitting all the edges should look like that area. If you feel the need for a bonding agent I know of one that may work the best, see if you can locate this product BA57 by Masterwall & make sure you read the data on applying it over a painted surface.
The best approach would be to use a paint remover in the area where you will over lay the finish over the existing after you chip back the edge.

 

[miamicuse]

I did it but it didn't quite come out as nice as I had hope.


First I applied one layer packed around the sides and back of the pipe. I misted it 2-3 times a day and put a sheet of visqueen over it for a week.

Then today I did another layer, waited 2 hours and did the texture.

I can't get the texture right. It looks to me like it's been patched and the more I messed with it the worse it looks. I don't know, may be I need to grind it flush and do the texture again. The stucco mix is fine I know it's the lacking of skills. I don't think painting it will make it look better it probably will make it stand out more.

 

[ClarenceBauer]

You should have dashed the finish on with a large paint brush keeping the brush say about 12 inches from the wall. After about 3 or 4 min. very lightly trowel it just flatting out the top of the dash coating.

 

[miamicuse]

I wonder if I should use a grinder to grind it flush and try the texture again.

 

[ClarenceBauer]

Your call on removing the existing texture & redoing it.
If you elect to grind off you should do it while the Stucco is still "Green" so you get a good bond.

 

[miamicuse]

Well I found out I didn't need to grind I took a stiff putty knife and was able the scrap off in multiple passes pretty much the thin layer I put on yesterday, I then put on a thin smooth layer again. Now I am waiting for that to set a little before I try the dashing again.

Is the finish mixed to the same consistency of much thinner? Yesterday it was the same consistency but it was dashed it was a larger chunk on a knife and "flinged" to the wall.

 

[ClarenceBauer]

Make the dash mix like very heavy whipped cream.

 

[miamicuse]

Well, I did the finish again, twice actually, and I am not sure it's any better than the first try, may be a little better. I got 1/3 of the dash on the wall, 1/3 on the brick deck, and 1/3 on my pants LOL.

I think I will just go with this unless I wake up tomorrow and want to give it another try.


Do I need to wait 28 days to prime/paint this?