I am currently renovating an old building into commercial lease space and the building needs a new coat of stucco.
The exterior walls are ‘cinder’ block, I mean the old blocks actually made from cinders,and they had been stuccoed as an original finish.
Looking at the surface yesterday and planning my attack,I see a deteriorated skin of some sort of a white,powdery base coat…then a 1/4″ (more or less) coat of smooth mortar stucco,and then several layers of paint.
Now I am trying to decide how to place a new traditional stucco layer on this mess.
One approach would be to place stucco mesh on the entire surface and treat it as a new wall.Getting the wire mesh fastened to this old ‘cinder’ block would be a chore,and expensive.
The thought I am entertaining at the moment: Pressure wash the walls…mortar patch any problem areas…apply bonding agent…and then……….I wonder if I could then just apply a color coat without applying the base coat?
What do y’all think?
what the heck
was I thinking?
Replies
If you're going to sub this out I'd get your sub on site and talk it over.
If you're doing it yourself, here's how it looks to me from here. I've used bonding adhesive over clean, solid old masonry with pretty good results. With the paint you've got to deal with, I have my doubts. You either need a solid substrate (no flaking, spalling, i.e. good solid material) or you need to re-lathe. With the situation you're describing it can be tough to get good results unless you re-lathe.
Stucco neting over block really isn't that bad to install. Short case-hardened nails with washer heads go in pretty easy if you hit them with a 28 oz. rig axe. It's done all the time in the Southwest.
A little bit of acrylic additive in cases like this seems to help, too.
DRC
I have a similar situation with my house, except that it's multiple layers over original stucco. What I plan to do is get a sandblast sub to blow away the crumbly stuff, then patch and Xypex it.
-- J.S.
Anybody have any good ideas on where to learn more about stucco materials and application?
I'm thinking about trying my hand on a small non-critical project.
I'm good with a trowel, but I know very little about stucco chemistry or technique.
Is it plain lime mortar? Similar to parging? What is the color coat made from? What is a good supplier to consult?
I plan to stucco a new wall over plywood sheathing. I don't need to insulate via the styrofoam that seems common, but I do hope to keep moisture out of the structure.
Tips and hints would be welcome.
I don't know a lot about stucco application but I know that stucco applied directly to a wood surface with no other prep will flake off in a few years.
Happened to my parent's house. Stucco guy owed my dad a big favor, so he comes in and stuccos the house (dad bought the material). Three years later, when it's all cracking and falling off, we discover that he used no mesh, no backer, nothing. Just troweled the stuff right onto the T1-11 siding, cheap b*st*rd! And what recourse does my father have? None, considering it was favor.
By the way, I was living out of the country when this happened. Wish I would have been there to say something about the guy's application technique!
Rein,
I don't know much about stuccoing, but the little that I do know is this...Homes with styrofoam on the outside are usually stuccoed over with a pre-mixed acrylic stucco that comes out right out of a bucket. This is part of a whole EIFs system (Exterior Insulation and Finish System) that companies like Dryvit and Stowelit manufacture.
If you look close enough, you will see that the styrofoam is actually covered over with a nylon type netting that functions similar to the diamond mesh that real stucco uses. The EIF sytem products are expensive to use, and normally only qualified technicians can purchase these products.
In Columbus, Ohio, I see that EIFs are being phased out in the housing market for the real thing (cement stucco). Wood sheathed homes targeted for the cement stucco route are first covered in roofing felt. Some use 15#, and Iv'e seen some use 30# felt. Diamond mesh (metal lath) is then installed overtop of the roofing felt. I have seen "chicken wire" used instead of the diamond lath. I don't know which works best. I've then noticed a "brown coat" and then a finish coat applied. I don't know the recipes for the two coat mixes. Sure wish I did. I've heard of people using Type M masonry mortar with sand, but don't know if this is any good or not.
Let us know what you ultimaely do and the recipe you use. My house is currently vinyl sided, but I've been leaning toward ripping it all out and stuccoing my house as well. When I do, I think I'll add some brick or stone "quoins" at the house corners for a little decoration.
Good luck.
Davo
Thanks Davo,
My plan is in fact to go the non EIFS route. I have a new garage that is plywood sheathed. I am going to cover it with tar paper and diamond mesh.
I don't need more insulation on this structure and I want something that can take some dings, so I really don't want to go the EIFS route.
I guess I need to check out some more suppliers to see what the best mortar mix would be to use. My usual haunts for supplies don't seem to stock any premixed color coats so I figure it must be sold by suppliers to the pros.
Anybody know of any brands to look out for?
Half of Southern California is stucco and it's chicken wire inside. Hell of a lot cheaper, and lasts forever. Joe H
I'm in Toronto.
I don't have siesmic worries, but this climate can sure be hell on siding materials. Freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, freeze-thaw, etc..
Try using an air entraining admix to the stucco, this will have significantly more freeze resistance.
I didn't know they did that for stucco. I will look for it.
Here in Los Angeles, a well-known supplier of information/materials for exterior plaster applications - to include stucco - is a company called LaHabra. They shouldn't be too hard to find via the internet, or otherwise. Although I only undertake small stucco jobs, the guys I sub larger jobs to use this stuff. Not to mention, I frequently see these broken bags of mix scattered across the freeway. When I applied texture coats in the past, I tended to keep my mix more dry than wet. However, after watching true professionals sponge out wall after wall, they use their mix as wet as possible. And the difference is noticable. Different 'grades' of texture mix are used for different color additives (tinting). I hope what little I know helps!