Point access blocks (or single-stair buildings) are now an important part of today's discussions around housing supply in Canada. They are seen as a way to encourage more and different types of housing -- something we have been talking about on this blog for years. Here and here are two recent posts.

This week, I discovered the work of Conrad Speckert, who works at LGA Architectural Partners and has become a leading voice for this movement. Conrad completed his M.Arch at McGill University and, as part of his thesis project, he developed this website called Second Egress.

Since then it has grown to become a major resource for point access blocks. But most importantly, it has evolved into a catalyst for change. On April 18, 2022, he and David Hine (of David Hine Engineering) submitted this code change request to the Canadian Commission on Building and Fire Codes.

The ask: Allow a single means of egress for multi-unit residential buildings up to 6 storeys. (The current maximum is 2 storeys.) Well done, Conrad and David. This is a massively important request with far-reaching benefits, and so I would encourage all of you to check out his website and spread the word.

P.S. My second favorite part of his site is a section called Manual of Illegal Floor Plans. It's a catalog of highly livable single-stair buildings from around the world; all of which would be currently illegal to build in Canada.

Sometime next month we're going to be pouring a large concrete transfer slab at the second floor of One Delisle. Its function is to take the loads coming down from the entire tower above it and "transfer" them onto new structural elements, before being brought down to our mat foundation at the bottom of the parking garage.

Put differently -- and, as always, I should warn you that I'm not a structural engineer -- a transfer is used whenever you have a change in your structural grid and the loads don't have a straight path down to your foundations. Because whenever this happens, you're now introducing moment forces and those need to be dealt with structurally.

Transfer slabs are relatively common here in Toronto (which isn't the case in every market), but they are expensive and they consume a lot of depth. In the case of One Delisle, our level two transfer slab is 1.8 meters deep and it's going to contain about 1,200 m3 of concrete. (Some of you might also recall that One Delisle's mat foundation is over 4m deep.)

We were reviewing this with the team today and we think that we'll be able to pour about 100 m3 of concrete per hour. That means that this slab will take about 12 hours to pour! This requires a lot of coordination. Neighbors need to be notified, pumps need to be on standby in case of a breakdown, and so on.

Another major consideration is heat. When concrete cures it generates a lot of it. And with a thick slab like this one, I am told that we run the risk of the middle starting to overheat (especially with the hot weather that we've been having lately). The guideline limit is 60 degrees Celsius, so we'll be monitoring it for probably about 1-2 weeks following the pour.

I find these details fascinating. Maybe some of you do too. So once it's poured, I'll share a few photos.

Point access blocks (or single-stair buildings) are now an important part of today's discussions around housing supply in Canada. They are seen as a way to encourage more and different types of housing -- something we have been talking about on this blog for years. Here and here are two recent posts.

This week, I discovered the work of Conrad Speckert, who works at LGA Architectural Partners and has become a leading voice for this movement. Conrad completed his M.Arch at McGill University and, as part of his thesis project, he developed this website called Second Egress.

Since then it has grown to become a major resource for point access blocks. But most importantly, it has evolved into a catalyst for change. On April 18, 2022, he and David Hine (of David Hine Engineering) submitted this code change request to the Canadian Commission on Building and Fire Codes.

The ask: Allow a single means of egress for multi-unit residential buildings up to 6 storeys. (The current maximum is 2 storeys.) Well done, Conrad and David. This is a massively important request with far-reaching benefits, and so I would encourage all of you to check out his website and spread the word.

P.S. My second favorite part of his site is a section called Manual of Illegal Floor Plans. It's a catalog of highly livable single-stair buildings from around the world; all of which would be currently illegal to build in Canada.

Sometime next month we're going to be pouring a large concrete transfer slab at the second floor of One Delisle. Its function is to take the loads coming down from the entire tower above it and "transfer" them onto new structural elements, before being brought down to our mat foundation at the bottom of the parking garage.

Put differently -- and, as always, I should warn you that I'm not a structural engineer -- a transfer is used whenever you have a change in your structural grid and the loads don't have a straight path down to your foundations. Because whenever this happens, you're now introducing moment forces and those need to be dealt with structurally.

Transfer slabs are relatively common here in Toronto (which isn't the case in every market), but they are expensive and they consume a lot of depth. In the case of One Delisle, our level two transfer slab is 1.8 meters deep and it's going to contain about 1,200 m3 of concrete. (Some of you might also recall that One Delisle's mat foundation is over 4m deep.)

We were reviewing this with the team today and we think that we'll be able to pour about 100 m3 of concrete per hour. That means that this slab will take about 12 hours to pour! This requires a lot of coordination. Neighbors need to be notified, pumps need to be on standby in case of a breakdown, and so on.

Another major consideration is heat. When concrete cures it generates a lot of it. And with a thick slab like this one, I am told that we run the risk of the middle starting to overheat (especially with the hot weather that we've been having lately). The guideline limit is 60 degrees Celsius, so we'll be monitoring it for probably about 1-2 weeks following the pour.

I find these details fascinating. Maybe some of you do too. So once it's poured, I'll share a few photos.