Brick Residential Roof/Wall Detail 2

[AlohaBob]

I put veneer on a wall above the gable roof below. It can be supported by the wood truss and the studs easily. I considered lagging an angle to the stud backup behind pitched at the roof angle. I considered welding 10 gage wire to the angle 2 @ 4" oc vertical so every bed joint would have horizontal reinforcing. There's a little triangular space at the course ending at the angle which I figured to just fill with mortar.

There's other options. I could set an angle below the roof deck and move the end truss out to allow the brick to pass by, but I'm not comfortable with this. It seems to me more susceptible to water damage.

Some suggest build a 4" wall below adjacent to the backup wall to independently support the veneer. This seems like a waste and still promotes poor drainage.

I checked architectural standards and bia. I don't find any help.

Please review this and let me know if you found other good solutions. Or weigh in on the options I presented. Thanks.

 

[JAE]

The reason you don't see any published details on this is that it has traditionally been a code violation to support masonry or concrete via wood supports.

 

[AlohaBob]

I'm talking about architectural non-loadbearing brick veneer. Unless the code has changed, This is allowed for residential applications. The wood support is sufficient for code required deflections, shrinkages ect. There are specific code requirements about the bearing detail of wood support, but that's not my question or issue.

I'm inquiring about the practicality of the rake angled angle and alternatives.

 

[JAE]

- ok - for residential I see that the IRC allows brick veneer to be supported by wood as long at the L/600 deflection is provided for and with consideration for all loads.

The IRC 2000 has a couple of details that appear to be similar to your situation - see Figure 703.7.1.

 

[AlohaBob]

Thank you JAE. I don't have this reference. Can you describe what they prescribe in these details? I'll try to track it down through the internet.

 

[JAE]

Sure...

The detail where the veneer is supported by the truss is as follows:

1. They show triple rafters (this would be triple truss for you)which is adjacent to a vertical stud wall running up the side of the trusses.

2. Then, there is sheathing on the studs, on the truss-side of the stud wall. and on the opposite side.

3. There is roof sheathing on the truss (horizontal) that extends over the top of the triple top chord and stops at the stud wall.

4. There is a steel angle shown with a horizontal leg set on top of the top chord and pointing away from the stud wall. The vertical leg is pointing up with its back to the stud wall....the wall sheathing appears to be terminated at the angle.

5. The triple rafters (truss top chord) are shown with some kind of non-described fasteners tieing the wall studs to the truss top chord.

6. The trusses are nailed together as well.

7. The brick sits atop the horizontal angle leg, has flashing that comes down the wall and through the second course line of the brick - out the face of the wall, and then down to the roof sheathing.

8. There are veneer ties shown between the studs and the brick.

That is the first detail where the brick is supported by the roof framing. They have another detail where the brick is shown supported by the stud wall itself.

It is similar to the above except that there are no triple rafters/trusses - just one - and it is separated from the angle by a small space. The angle is shown fastened to the studs with a pair of screws/lag screws/bolts - not specifically called out. Other than that its the same.

I'd be careful about hanging brick on the stud itself - lots of eccentricity to worry about - the truss supported detail looks better.

 

[AlohaBob]

You see, I have a choice for laying in angles in segments, say like 2 foot widths horizontally. And step them up the roof. I would prefer to just run the angle at the slope of the roof and make a mechanical tie to the angle and the mortar to prevent movement. Movment of the brick isn't a problem for the horizontal segmented angle, but the detail must just be terrible to flash it, not to mention what it must look like appearance-wise.

Is there a clue in the detail about a preference in this regard?

 

[JAE]

Nope - but we have, in the past, called for a few intermittent plates welded vertically to the horizontal leg of the angle. Its tough to align these plates with the brick head joints by welding in the shop - but even so, a good mason can simply cut a few bricks to allow the vertical plates to extend up between and act as stops to any sliding.

Also, if there is significant brick extending in-plane beyond the end of the lower roof, that would be enough to keep the brick from sliding....if it is a dormer type return, though, you have nothing so I'd use the little stop-plates...you only need a few.

 

[AlohaBob]

Thanks JAE.

I thought this is a common framing condition. So for others with experience in this, please share your thoughts and solutions.

Even lessons learned by experience especially in regard to better flashing practices concerning this joint, I would much appreciate.

 

[blake989]

I have seen architects call for "step flashing" in these areas since the roof is at an angle and the bed joints are horizontal. I assume this is some pre-formed product for waterproofing these conditions. It looks ugly on the elevations but it must work. I agree with the stop plates, but are there types of brick ties that will resist lateral loads such as the brick sliding down the roof?

 

[JAE]

Usually ties for brick veneer are geared specifically for rigidity in the direction perpendicular to the wall. In this case, the movement would be parallel to the wall in a downward sloping angle.

 

[AlohaBob]

I'm still reviewing options for this rake wall roof detail. JAE, can you fax me or send me a pdf of the IDC detail you mention? bobsrd@tds.net and 262-896-2079.

Thanks

 

[JAE]

faxed on 10/28.

 

[AlohaBob]

Thanks JAE. I got it.

I am reviewing my details with a prolific local roofing contractor. It's guys like him who end up warranting the work anyhow. I hope to get some input there yet today. I also had some professors at a local university review the options I detailed as best I could describe.

I hope within the next couple days to find or develop an office standard for this condition for our regular use we can be comfortable it's the best standard after a rigorous review.

 

[AlohaBob]

This roofer showed me different methods he uses to accomplish his goal and to provide a system he's confident to warrant for the life of the structure. These would include continuous soldered flashings configured for my rake wall application. Also, since the best methods are expensive, he showed me alternate ways less expensive that still provide a system he would warrant for life. These essentially provide for a long lap of flashings in lieu of soldered joints. This will be my choice for a standard unless I see projects that can bear the extra cost, or I see a sure liability for a joint failure.

I'm led to abandon all the options I developed thus far in part. And choose only those elements that best suit the intent and make for an efficient effective treatment.

I'll provide solid blocking for continuous bearing. L2x2x1/4 x 2" long clips to solid block backing lagged behind at 16" oc to address a slipping problem. These will be mortared between head joints in the brick. I'll use a through sheathing flashing above lapped by the building paper. This flashing will penetrate the brick shedding the water over a counter flashing with a special crimp which covers a lower step flashing at the brick-roof intersection. The crimp joins the through flashing and the counter flashing rendering a sawcut in the brick unnecessary.

Unfortunately, the flashing is exposed to view. However, we can order the flashings in whatever color we wish, even in Kynar finishes as well as copper, so coordinating with the architect, we can at least match initially the trim schemes of the project.

Although given a choice, I would prefer not to see the flashings, this exposure does make a statement, that being, the highest standard and best available practices for treatment of the issue of water penetration has been carefully addressed.

Thank you gentlemen for your feedback. I'm pretty confident in what we will use, but I welcome further evaluation as these things are surely an art and continuously evolve with new technologies and practical experience it seems.

 

[TomHubbell]

While the 2003 IRC does have details showing exterior masonry veneer supported by wood/light frame steel studs (p. 214), these appear to be applicable for Seismic Design Categories A, B & C only, leaving all of us in D1 and D2 out of luck (R703.7.2, p. 209). Note that if you're in SDC A, B or C you still have certain veneer height and braced panel restrictions.

Since the IRC is prescriptive based (and I am in SDC D1), I turned to the IBC for guidance on supporting brick veneer with wood. In the Wood section I found a reference (2304.12, p. 457) regarding woood supporting ANY masonry or concrete. This section states it is not allowed but goes on to give exceptions. One exception is for veneer (brick, stone & concrete) that can be supported on an approved treated wood "foundation" (quotes are mine). Interior brick veneer can be supported on "wood floor construction".

My interpretation is that you can support exterior brick veneer on a wood foundation - but not a wood floor or wood wall. In this regard, the IBC seems to be more conservative than the IRC.

Thus, I presume that to support an exterior brick veneer in SDC D1 or D2 areas, you need to use non-wood (steel/concrete/masonry) support all the way down (beam and supporting columns) to the foundation (which, with restrictions) may be treated wood.

 

[AlohaBob]

Thanks Tom,

It makes sense, seismic in-plane forces say conservatively, make the loadpath direct to the foundation. We're SDC A and B here mostly. So the detail here is common. It's not common that I recall in California. I recall researching and legally supporting interior brick fireplace veneers on floor framing. I don't think I ever addressed my roof detail here, there. There, it would make sense laterally to bring the veneer through the roof diaphram directly to the floor - preferably to the foundation. The detail is a headache here. It would be even worse there.

 

[mauisatish]

I am looking for some help for designing a concrete box with 7" slab supported on all edges. The slab is 12'=x7'. The center of slab has an opening 8'-10"x4'-10". This opening is covered with steel plate. Slab is supported on all edges with 6" thick walls. Where can I find any help to design the concrete slab?

Thank you,

MauiSatish

 

[AlohaBob]

MauiSatish,

Here isn't the place to do design work. Your project sounds very simple, so if you were to bring a sketch to a structural engineer near you, I think within a couple hours he can give you everything you need to build this safely, meet code requirements, and conform to your conditions.