Wood Joists in Brick Masonry Pockets
Wood Joists in Brick Masonry Pockets
(OP)
In this area typical brownstone/rowhouse construction used 3x dimension lumber pocketed into brick masonry 'party walls', walls that are shared by both neighbors and therefore not exposed. These joists were bricked in tight, no air gap, and had a fire cut at their ends.
When doing joist replacement, new joists into existing pockets, the question has come up about protecting the ends of the joists. My interpretation/understanding about wood in contact with masonry was that this applied to exterior walls or walls likely to get wet. These are essentially interior walls as they are shared by a neighbor. I've had some suggestions to wrap the ends in a membrane - but that seems like a lot of work and I am not confident they'd get it well sealed anyway.
The existing joist ends are typically fine in these conditions and have lasted 100+ yrs, unless there was a specific water leak/issue at a particular location.
Any code reference/guidance on when you are required to use treated wood, or to protect the ends? We could leave the pockets open but I don't like the way that feels - I prefer some connectivity.
When doing joist replacement, new joists into existing pockets, the question has come up about protecting the ends of the joists. My interpretation/understanding about wood in contact with masonry was that this applied to exterior walls or walls likely to get wet. These are essentially interior walls as they are shared by a neighbor. I've had some suggestions to wrap the ends in a membrane - but that seems like a lot of work and I am not confident they'd get it well sealed anyway.
The existing joist ends are typically fine in these conditions and have lasted 100+ yrs, unless there was a specific water leak/issue at a particular location.
Any code reference/guidance on when you are required to use treated wood, or to protect the ends? We could leave the pockets open but I don't like the way that feels - I prefer some connectivity.






RE: Wood Joists in Brick Masonry Pockets
RE: Wood Joists in Brick Masonry Pockets
Not sure if I would allow the use of untreated wood joists in those masonry pockets. But, maybe the calculations for the joists would look good to me.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Wood Joists in Brick Masonry Pockets
If it was a new building I wouldn't like the detail - but after seeing them strip out joist after joist with a perfectly sound 100yr old end I'm more confident in it for this application.
RE: Wood Joists in Brick Masonry Pockets
RE: Wood Joists in Brick Masonry Pockets
RE: Wood Joists in Brick Masonry Pockets
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Wood Joists in Brick Masonry Pockets
RE: Wood Joists in Brick Masonry Pockets
However, if the pocket is an exterior masonry wall exposed to the weather, I would provide a 1/2" air gap at the sides, top, and end, and use pressure treated joists for that span. I would also look into providing a small metal bearing plate if it was practical to do so.
Re3membver to provide the thru-the wall ties to the joists if embedded tie straps are not there already.
Mike McCann
MMC Engineering