Supporting Brick Veneer on Sloped Wood Roof 1

[T_Bat]

Hey everyone,

I have a job with a brick wrapped cupola. At the case where the veneer sits on the down slope, I'm not sure how to support it. I'm thinking of ripping some blocking to so that my brick angle can sit flat (no bent plate) and I can tie it back to the cupola framing. I assume they architect can flash behind the brick, over the angle, and down the blocking. Has anyone ever run across this before?

For the other direction, I'm planning to follow the IRC provisions and weld tabs to the angle.

 

[JoelTXCive]

Unless I'm missing something.......the angle (lintel) IS the support for the brick.

If the vertical leg of the angle is properly fastened to the upper stud wall/beam, then you need nothing underneath the horizontal leg of the angle. A piece of counterflashing can be used to cover the transition from roof deck to brick wall.

Also, as a side note, builders always get in trouble with drainage on veneer brick walls over roofed areas. There needs to be an escape avenue for water. The building paper/tyvek etc, can be lapped over the steel angle and then you can put weep holes in the brick to get the water out. Even if this is outside your scope as an engineer, I might throw a comment on the plans regarding drainage and flashing being the builder's responsibility and not yours.

 

[T_Bat]

Thanks Joel - I guess I want to have belt and suspenders here. I don't like to rely just on the angle screwed to the studs behind for support since we are right down at the base of a stud - and a stud that will be cut on an angle at that. I guess I'll just design the screwed connection and then specify the blocking for good measure. Good call on the wrap - I'll talk to the architect about this one.

 

[HouseBoy]

Why do you have/need the angle at all? It seems that the angle might be needlessly complicated (relating to aligning the holes with each stud).
If everything is ultimately supported by the wood (angle screwed to the studs, studs supported on the trusses etc) then the wood is doing all of the work regardless so... it seems that resting it all on wood blocking would be possible.
Making sure the wood blocking stays put will be important but that might be doable with a broader plate (maybe layered plywood) fastened to the trusses.
Perhaps you want to have something that is reliably stiff in place to prevent differential movement around the cupola. I wonder if plywood sheathing on the cupola would suffice.

 

[msquared48]

I would never rest the brick on wood. Great scenario for rot to develop.

Keep the angle.

Seems like an odd, crazy Architectural detail that will increase the liability of the structure, all for the sake of what???

Mike McCann, PE, SE (WA)

 

[T_Bat]

MS - I'm definitely not advocating for brick to wood. I just mean to put blocking under the angle. I'm leaning towards a bent plate so I can get an 8" vertical leg. That should get the leg far enough up the studs that I can get (2) screws through the angle to the stud. Blocking will be below the angle and nailed to the trusses.

HB - I'm not sure I follow exactly what you mean, but the cupola will be sheathed and we a specifying a nailing like a shearwall.

 

[HouseBoy]

TB
If I understand the set-up, there are simply 4 steel angles, one on each face of the cupola and the angles are screwed to the wall studs. (I like the idea of a longer vertical leg too).
I'm just thinking that the angle will add very little to the support since the ultimate support for the angle is provided by the screw attachment into the studs.

Most likely there is not very much brick involved here.

We all agree that brick should not be touching the wood. I'm thinking metal flashing would be most appropriate and in that case, the brick bearing on some kind of wood blocking seems permissible.

 

[JoelTXCive]

While building houses in my pre-engineering days, we would nail double 2x12 blocking between the studs all the way around the cupola.

The mason would then attach the lintel with lag screws to the blocking.

I didn't realize at the time, but the nails attaching the blocking are carrying all that load in shear to keep the wall from falling off the house.

Hopefully the mason used lots of brick ties on those houses........

 

[JoelTXCive]

I found this article on my home computer. It is written by a PE and discusses structural items as well as flashing setup for veneer brick over a wood frame.

They have a nice detail too that the architect can copy if they want.

Enjoy!....

 

[XR250]

The author did not address the attachment of the blocking ends to the studs to resist the eccentric torsion of the brick lintel - which can be significant with alot of brick. I guess we could also get into the cross grain bending as well, but that may be nitpicking :>

 

[T_Bat]

Thanks Joel - very helpful.

XR - I agree... running the actual numbers on the torsion on the ends of the blocking is pretty wild. The connections, if actually designed, get pretty wild. Fortunately here the brick load is small and attached directly to the studs. I'm designing the steel lintel attachment to fully support the brick - then also specifying they provide blocking below. As mentioned... belt and suspenders here.

It's interesting to note that in all my google searching, I can't find many good pictures or commentary addressing this situation. If the brick load were any larger I would be suggesting they paint some siding and forget about brick.

 

[dhengr]

T_Bat:
This might be a good application for one of the several ‘thin-brick’ veneer systems. This would certainly lighten the load all around, since we know so little about the size of the cupula, the cap’y. of the trusses, nasty heavy load detailing and deflection/movement on a high slope, etc. Good detailing, water plane and drainage design, flashing, movement joints, etc. are important in any/either case. How do you handle the brick support and flashing, etc. as the brick moves up the roof slope, on the ends of the cupula? Put some good notes on your drawings about some of these issues. Many times, if you leave water plane, drainage, flashing, etc. up to the Arch. it gets neglected or forgotten during the picking of the brick color; never to be thought of again until you get a call because the roof or ceiling is leaking. Then, it will be your fault.

 

[T_Bat]

Great points dhengr - some of my fear is that this for this "small" job the level of detailing from the arch may leave a lot of things up to the contractor. Not always a good thing...

As for the other end of the cupola - I would approach similar to what the IRC uses in R703.8.2.2 "Support by Roof Construction"

 

[MotorCity]

I like your belt and suspenders approach. Honestly, until I saw your approach I never really came across a method that I was comfortable with.

I like the notion of having a truss vertical and diagonal directly below the wall. Having the blocking below prevents a moment from being imposed on the back up.

I see the potential weak link being excessive truss deflection and proper flashing so that water does not find its way to the wood blocking. I would also take a close look at the load path
regarding how the lateral force and the bottom of the brick finds its way into the truss.

 

[JoelTXCive]

Most of the residential production builders in Texas avoid putting brick over the roofed area. Aside from more complicated structural issues, it's a nightmare on the flashing side. When I built homes, I only saw bricked areas above a roof line on custom homes.

The production builders will use Hardi-Siding or Stucco when they have a exterior wall above a roofline, which is much easier to build.

To get the flashing correct in brick regions, you have to have the roofer, mason, and the cornice (exterior trim) crews all working together. Since the whole industry operates with individual sub-contractors performing individual tasks, this is incredibly difficult to do if you are building a large volume of homes at once.

Dhengr - To handle the support up the sides, you just run the steel angle at an angle. Small tabs are welded to the angle and they serve as little shear keys to keep the brick from sliding down.

I forgot this fact, which further complicates the flashing. Remember the roofer is going to run step flashing and counterflashing down the sides of the brick in the sloped regions. That vertical leg of the step flashing will project ~6" inches up the brick face. That means the flashing that sends water from the back of the brick (tyvek region) needs to be at least 6" up the wall. Otherwise the moisture from behind the wall will get kicked out behind or underneath the step flashing.

I'm telling you, this stuff is a flashing nightmare. I would definitely put a note on the plans saying it's the contractors responsibility to figure out the flashing.

 

[T_Bat]

There is a good article on this by the SBC. See below - shows an example of the angle down the slope with tabs.

Link

 

[XR250]

Ironically, most brick above framing around here is not thru wall flashed and I rarely see a leakage problem.

 

[Ron]

Joel is correct...keep the angle and leave open underneath for proper waterproofing.

There is no waterproofing shown in the detail. This location can be critical for damage so make sure the detail shows proper waterproofing of the brick cavity and of the wall to roof transition behind it.

 

[JoelTXCive]

While building, I probably saw the flashing installed wrong 85% of the time. I'm sure that I built homes with the incorrect detail too, and it was never an issue. This was just luck though.

The clay brick is porous, but it takes and extended amount of time for the water to migrate through. In a normal 1 day rain event, the brick will get wet, but not wet enough for large amounts of water to migrate through. It's a totally different story in an extended rain event.

As an example, My parent's home was built without through flashing 18 years ago. It was not an issue until Hurricane Harvey, and then they had significant water damage inside due to water leaks in the bricked 2nd floor regions.

During Hurricane Harvey, we had about a week long rain event, combined with high winds driving water into the wall. The wall stayed wet for a week never got the opportunity to dry out. Eventually it became 100% saturated. Once it hit that point, water flowed like a river inside the home. We could access part of the back side of the wall from an attic. You could see the water running down the tyvek, but it had no way to escape except through the house.

The only real solution to the problem is to tear the brick off and re-flash properly. Unfortunately, that will be very expensive and there is no way you are going to be able to match the brick color. My parent's also looked at coating the wall with some waterproofing coatings, but in the end they did nothing. I don't think the coatings are good for more than a few years out in the sun. Their current strategy is just to hope we don't get another Harvey, or they will put a big plastic sheet on the wall if we get another week long storm.

 

[OldBldgGuy]

I guess those of us who have seen masonry supported on wood and really have nothing good to say about it have all declined to chime in on this one, but the part that baffles me is how many of you take masonry supported on wood as a common occurrence. It is essentially not even allowed in the Canadian and Ontario Building Codes (with some minor exceptions). I can say I've seen many many variations on building techniques in 40+ years and old buildings are the place I poke my nose in most, but I have never seen a brick-clad cupola supported on a wood-framed roof. I think we must live in different worlds, although the current trend for gluing slices of brick or stone or coloured styrofoam on wood framing gives people the impression that masonry is allowed anywhere.