Parging Help needed !
I have a poured concrete foundation that needs parging, which is straight forward on most of the house, however, on some walls the 2×6 untreated sill plate is exposed (1.5″). The house has an aggregate finish which in those areas is 1/2″ proud of the exposed sill plate. Any ideas on covering the sill plate before parging?
cover the sill with strips of aluminum ? galvanised? or just parge the wood?
Any ideas greatly appreciated all.
PS. location is in Quebec, Canada, so subject to freezing and summer heat.
Replies
Double layer of grade D building paper and a strip of expanded metal lathe nailed to the wood ought to do the trick.
Make sure the metal lathe goes on right-side-up (no joke), and flash the top so no water gets behind the stucco, . . . I mean parging. <G>
You can use stucco stop and Z-flashing over that, or anything else you want that sheds the water to the outside.
The double layer of paper is important, it gives you a shear plane. That will help in severe freeze-thaw situations.
If you are using regular old Portland cement and sand mixture, you might also consider adding Anti-Hydro, which will give you a much stronger and more water-resistant result.
Alternately, you can also use an acrylic fortifier for a more flexible and impact-resistantt product.
Excellent reply Catskinner.
Please educate me. Which is the right side of the lathe?
blue
Thanks, Blue.Because of the way expanded metal lathe is made there is an angle in the perforations or slits relative to the sheet of metal. I know that's an awkward description, but I don't know how else to explain it.If you look at a piece of expanded metal lathe and imagine it nailed to the wall, if you hold it one way, those little perforations or slits form a shelf that holds the stucco onto the wall. The plastic stucco slides into the wall and locks on good.But if you hold the lathe any other way (like flip it over or turn it around) when you go to put the stucco on it all slides down the little ramps and falls off of the wall, usually all over your boots.There is no way to make it stay on the wall.This is funny as h#ll to watch. <G>
Thanks for the seminar Catskinner. Theres some lath at the house next door. I'll check it out tomorrow.
blue
This is funny as h#ll to watch. <G>
Is that why you were laughing at me? :-)
Could we say that expanded metal lath is like louvered heating duct registers...?
David, that is a very good analogy. I was thinking along those lines. I've never really studied lath that closely, but now I'll take a better look.
blue
I got it... grab a scrap of lath before lunch and use it to grate your cheese.
David, you aren't that far off. A scrap of metal lathe wrapped around a block of wood makes a surprisingly good tool for rough-shaping contours in gypsum plaster.
Thanks guys for your help! A contractor up here told me it would be a 2 1/2 day job, where he would cut strips of galvanised sheet metal into 2 inch strips, nail the strips into the sill, then coat the foundation and strips with a concrete latex adhesive then parge it all.... the tarpaper and lathe way makes much more sense! BTW it only about 120 sq ft. of parging. He told my wife he would only charge us $60/hr.
Glad I checked here...
I'm glad you checked here, too. It's sad to see a house get messed up because of bad drainage details.It's a common mistake. Most of the construction defects lawsuits in California are due to moisture getting inside the building envelope and not getting back out.When you install your Z-flashing over the stucco stop, make sure that the siding and housewrap overlap the top part of it so that any water that has gotten behind your siding runs down the housewrap onto the Z-flashing and gets kicked out over the front of the stucco stop.Otherwise the water will lay against your sill plate and that's where the trouble happens.Positive and reliable drainage to the outside of the building envelope is the key principle here.Glue over sheet metal strips would actually hold for a little while. But the freeze-thaw would eventually pop all the parging off, and you would end up with water behind the parging wicking up the wall into the wood.