Have an existing fluted concrete block building. Client needs an air barrier to be applied to the concrete block, interior not to be touched. Any suggestions?
They had a similar problem in Chernobyl. Here is how they solved it.
https://en.wikipedia.org/wiki/Chernobyl_New_Safe_Confinement
Michael, that is a very funny suggestion, and a very interesting project!
Jerome, try Prosoco, they might have something you can use. Or if you are okay with using a black tar look, try Henry’s 33MR
not the same conditions
Michael please don’t take offense, but you are an odd man, just the fact that you use Wikipedia as a reference source is bothersome.
I agree with reaching out to Prosoco, they are on my list as is BASF and WR Meadows, was hoping to receive mention of actual products to research (not on Wikipedia).
The intent is for a paintable surface or a clear (preferred) finish.
Gypsum board is an air barrier. If the interior has gypsum board, then it may be a matter of sealing the gaps between the gypsum board and floor surfaces, outlet/switch boxes, doors, windows, and wall areas above suspended ceilings to the roof deck. The roof may need treatment depending on its construction.
An exterior treatment to the block only may not seal all the possible concealed pathways.
Jerome
No offense was taken. After all, I have been certified as a CCS – Crazy Construction Specifier.
Sometimes I deliberately play The Fool to provoke fresh thinking or provide commentary. Regarding this project, for example, I am suggesting that the client’s requirement might be a disaster – taking a porous material with high potential for crack formation at joints, and wanting it to be air tight but unwilling to entomb the split faces with a parge coat or cladding.
Regarding use of Wikipedia, I had previously spent an hour online studying the Chernobyl project. It is fascinating.
Gypsum board is not an option, interior is not to be accessed…perhaps Michael know something I don’t?..but I am pretty sure this is not a nuclear accident cover up.
Oh if only I had time to study fascinating projects…rather than last minute requests from clients…I think there are some clients who wait until end of the day to bombard me with these questions…
In California, we have a separate code called “The California Energy Code”. Since the 2013 edition, this has been the place where air barriers are defined and required for new construction. The code list predictable materials that meet the requirements, but also lists some exceptions which may help you if Florida has similar codes based on the IBC.
"…the following materials shall be deemed to comply with Sub-chapter 5 if all joints are sealed and all of the materials are installed as air barriers in accordance with the manufacturer’s instructions:
- Concrete masonry walls that have at least two coatings of paint or at least two coatings of sealer coating."
The remaining exceptions wander off into other materials.
A liquid-applied product may (only “may”) seal a surface as porous as fluted concrete block sufficiently to minimize air penetration through the block. But for the envelope as a whole to function as an air barrier, more than just the CMU has to be considered. What about sealing gaps around penetrations through the CMU for windows, doors, louvers? Normally (concealed) transition strips are used for this purpose, but they are not beautiful and typically are not intended to be visible.