MASONRY

December 2019 Newsletter, Updated 5/11/21

This month’s value engineering topic is masonry. It will cover brick returns, efficient pier width, lipped brick, brick size, brick material costs, “specials”, blending, thermally broken brick ties, relieving angle frequency, relieving angle size, stainless steel drip edges, dropped or hung relieving angles/lintels, CMU size, CMU lintel type, thermally broken relieving angles, thermally broken relieving angles, bond beam details for plank bearing, rebar splices in CMU partitions, special brick bonds, lateral support for CMU partitions, grouting requirements, and quality control/assurance standards for AVBs.

If brick returns at typical window masonry openings are shown, are they indispensable to the design?

The issue of brick returns at windows seems to come up on every project. By brick returns here we mean windows set in from the face of building by more than the depth of the side of the brick (requiring the veneer to turn the corner and return into the MO). Although not returning the brick increases cost in cavity closures, clips to structurally cantilever the window, etc., the added brick surface area of the returns (especially if the returns require “specials”) has—to date—outweighed these additions. Brick returns have been relatively infrequent for us—on affordable or market rate housing. To my knowledge, we have never yet installed them for a typical window condition. (This will change shortly due to 1490 Southern Boulevard, which has a brick return at one side of the window and an aluminum return on the other). Despite their cost, as cavities get larger with increased insulation requirements, brick window returns have become more tempting so as to avoid complicated window installations.

Figure 1 — A Brick return detail from 1490 Southern.

Are masonry pier sizes efficient?

It is important to check that brick piers have been selected at efficient sizes that also work with coursing so as not to require excessive cutting. All else equal, the more field cutting that must occur the more expensive the overall masonry contract will be. Cutting represents additional handling, labor time on the saw, and often much higher material waste factors if the cuts must be discarded. Masonry bidders are looking for big, productive walls and well-thought-out piers. As an example of what not to do, 1 John Street (which will come up repeatedly in this article due to its extraordinarily expensive masonry features) actually had pier sizes at the bottom of the building smaller in total width than the minimum size which could be ordered from the manufacturer.

Figure 2 — Sketches produced for 1 John Street to determine the extreme waste factors there and a photo of a typical brick pier.

If lipped brick is shown, is this indispensable to the design?

Like brick returns, whether to provide lipped brick seems to come up as a question on almost every project. Architects and owners would prefer not to see the thicker joint at the relieving angle (this joint must accommodate the thickness of the angle itself). For that reason, they often specify a “lipped” brick to conceal the angle. This introduces “specials” to the job and, with them, additional cost. (More on this later.)

Figure 3 — A lipped soldier course shown for Betances V.

Is the brick size selected by the architect a cost-effective size?

All else equal, the larger the size of the brick as expressed on the façade the better the production rate that can be achieved and the lower the overall cost of the masonry work. This effect is amplified in a prevailing wage or union environment where the ratio of labor cost to material cost is increased. For the reason above, we typically recommend utility sized brick for affordable housing. Architects and clients, almost invariably, prefer smaller bricks to larger ones. Note that there are several options in between a utility brick and a traditional modular brick that have varying production rates. Be careful when proposing changes to brick sizes though—the architect may have to adjust their MOs and floor-to-floor heights so that coursing will work if the building has been coursed for a different size. One useful aesthetic/cost compromise is to use a less efficient brick size lower down on the building where the bond is more visible and a more efficient size above where it is less visible.

Figure 4 — Common brick sizes

Is the brick selected by the architect a cost-effective material?

Brick material cost has a huge range. In recent years, we have seen it vary from $6 per square foot (the Bowerston Shale #208 Smooth used at Compass 2) to $32 per square foot (the Petersen Tegl K91 “Kolumba” used at 1 John Street) for non-specials. This is an easy cost to check once a selection has been made by the architect and it is important to do so as early as possible. A common misconception is that brick material cost is completely dependent on the degree of luxury of the building. Luxury plays a part, but in fact the cost seems to have far more to do with the whims, tastes, and accountability (or lack thereof) of the architect. For example, we have seen a $6.00 per square foot brick used on luxury rental housing and we have seen an almost $20 per square foot brick used on housing for the formerly homeless (the latter being the blend used for part of 985 Bruckner’s facade). As was pointed out in relationship to brick size, a useful compromise is to specify a more expensive material lower down on (or only in the front of) the building where it is more visible and a less expensive material above or behind.

Figure 5 — Petersen Kolumbas: hand-made by Danes and extremely expensive.

Does the design and brick finish require too many “specials”?

“Specials” refers to any bricks apart from the standard unit for that building. For buildings with non-glazed, non-lipped bricks (and right angles) there may be no specials at all. But for a building with odd angles and/or glazed brick (where the color or pattern is not “through” the brick) or other special outside features like rustication, you may encounter all varieties of specials. With these types of bricks, every building corner, every return, every header course, every sailor course, every rowlock course, and every shiner course (I had to look up those last ones) represents a special piece that needs to be ordered. Only the typical stretcher and soldier courses will be standard. These questions are important because specials are expensive (they are ordered in low quantities and brick manufacturers can’t use their typical production procedures to make them). For example, the specials for the Endicott Dark Ironspot Velour at Second Farms are $35 per piece. That’s over 14 times the cost of the utility stretcher for that project. Common specials you may encounter on projects without glazed finishes are lipped stretchers and lipped corner stretchers. The latter are especially expensive. The lipped corner stretcher for the Ashberry Velour brick at Riverwalk 8 is over 5 times the cost of the stretcher. Corbeling and other details may require special solid bricks without cores but we see these conditions relatively rarely.

Figure 6 — Special glazed corner bricks at One Flushing and 1490 Southern

Figure 7 — The "Zipper" at the corner of Carmel Place illustrates the need for specials for corners in glazed brick facades. However, in this case the zipper was 100% intentional by the architect…

Is the selected brick manufacturer capable of delivering all brick blends specified in the documents pre-palletized?

Most blends specified by architects are proposed to them by manufacturer representatives and so those blends are typically capable of being pre-blended by the manufacturer. However, sometimes architects will specify blends that cannot be delivered pre-blended on pallets. In those cases, masons will have to do the blending on-site which is time-consuming, expensive, and can lead to very visible errors if not done flawlessly. For these reasons it is important to question the blending requirements and eliminate any blends that cannot be provided by the manufacturer. This is a relatively uncommon problem, but it has come up in the past. For example, 1 John Street, which had what is still the most expensive façade Monadnock has ever built, required a different blend at every single floor. Because the Danish brick manufacturer refused to provide this, all this work had to be done in the field.

Figure 8 — 1 John Street façade. Although blends were precise at every floor, the change in color and pattern was ultimately barely decipherable.

Are thermal breaks (or is stainless steel) shown for brick veneer anchorage/”ties” and are these measures really required?

As passive house and other high-performance building have become more prevalent, we have seen these high-performance (typically expensive) details sneak onto drawing sets for unrelated projects. In preconstruction, we often must comb through all the exterior wall details to eradicate stray passive house notes. One example of this is thermally broken brick anchors (which reduce heat loss through conductive metals in the brick anchors by introducing a plastic isolator). It is important to remember that even in a Passive House context, these anchors may not actually be required (depending on the efficiency of the rest of the features of the building). We also sometimes see stainless steel anchorage specified for this because stainless steel conducts less heat than galvanized steel.

Figure 9 — A Hohmann & Barnard Thermal 2-Seal anchor.

Are there too many relieving angles?

Opinions differ on this, but Monadnock’s official position on the issue at the time of this writing is that (for typical floor heights) relieving angles need not be provided more frequently than every two floors. (Years ago, three floors might have been acceptable…) Yet we frequently encounter drawing sets that specify relieving angles at every floor (and we frequently build the same). Relieving angle pricing has recently ranged from $50 - $75 per lineal foot installed (with open shop labor) but there may also be savings in the brick itself (if lipped brick is required) and in caulking for the joint that results from the angle. However, for projects with small brick piers, it may not be worth trying to eliminate the relieving angle at every other floor. (The savings will be relatively small because angles will always be required at every window MO to support the brick above.)

Figure 10 — Relieving angles used at every floor at Second Farms

Is the Relieving Angle size specified appropriate?

It’s rarely possible to change the relieving angle size once determined (if determined properly by the architect and engineer) but it’s always worth reviewing anyway. The reason it is generally fixed is that it is governed by the conventional 1” air cavity and by whatever cavity insulation is required for energy model compliance. Cavity insulation could be moved inboard of the CMU to lessen the overall cavity and angle size; however, in our climate, moving additional insulation inboard of the air-vapor-barrier can create dew point issues. (Dew point is beyond the scope of this article but by dew point issues we mean that water vapor in the air may condense inboard of the AVB and create mold problems. General best practice is to keep all insulation on the outside of the AVB.) When looking at angle size, it is important to find out whether the dimensions are obtainable with commonly available steel angle sizes. If not, a bent plate will be required and the change from angle to bent plate is a major inflection point in pricing.

Figure 11 — Relieving Angle Installed at 509 West 38th Street.

Are “dropped” or “hung” relieving angles/brick lintels really required?

The most efficient installation point for a relieving angle is right at the edge of slab, spandrel beam, or lintel so that the back leg of the angle is braced by the building structure and the angle is prevented from rolling inward without the addition of “kickers” or other lateral support. This is the reason that windows on structural steel or CIP concrete jobs are typically tight to the underside of the slab above. However, occasionally architects will draw the masonry openings lower for aesthetic reasons (most commonly at the ground floor). In these cases, it is work asking if it is possible to change the opening location to eliminate the need for a hung angle and the resulting lateral support work.

Figure 12 — A particularly bizarre hung lintel detail cooked up by Fx Collobarative and Desimone. This one might not even have worked structurally, let along economically, had we not changed the design.

If stainless steel (SS) drip edges are shown, are they really required?

Typically, architectural details today show SS drip edges at the outside of relieving angles to direct water away from the wall. We did not always install this detail (in the 1970s Monadnock wasn’t even flashing buildings…) but it is rapidly becoming an industry standard, at least in NYC. The jury is still out on this and Monadnock is officially indifferent to it as a requirement (we could not reach consensus in the executive meeting), but it certainly adds cost. Apart from cost, this piece tends to get mangled during construction and can make the façade look worse (with or without a hemmed edge at the drip edge itself).

Figure 1 3 — Drip edge detail from 1490 Southern without a hemmed edge shown.

Figure 14 — A drip edge detail for H&B showing a hemmed edge.

Can 18” CMU be substituted in lieu of 16” CMU?

At the time of this writing, most masonry bidders will provide a lower cost for 18” CMU than 16” CMU due to the improvement in production rates from the greater piece size. However, we should be careful when making this substitution because the cell spacing will change and this can create tricky conditions for the minimum spacing for vertical reinforcement specified on the drawings. (Drawings and standard details are usually developed with 16” CMU in mind.) Like brick size, this cost savings is amplified in a prevailing wage or union environment. At the time of this writing, no mason has yet proposed a size larger than 18” as a cost savings (that the author is aware of), but this is conceivable in the future.

If HSS tube steel lintels are shown, can precast be substituted?

Up until the last couple months, we would typically reverse this question—i.e., if we received a drawing set showing precast lintels we would ask the architect and our client if we could substitute galvanized HSS tube steel lintels. Two things have changed: (1) precast lintels have come down in price significantly as the industry became used to them and more suppliers entered the market, and (2) architects have been more weary of using the old work-arounds on lintel fireproofing requirements. (Precast lintels are by nature fireproof.) Considering these two facts, we now typically describe precast as our preference (except for very wide openings where the precast lintel depth may exceed practicality). Precast lintels also offer benefits for Passive House construction due to their superior thermal isolation.

Figure 15 — Galvanized HSS lintels on the left from 1490 Southern and precast lintels on the right from Marine Terrace

If Fero FAST brackets are shown for relieving angle support, are they really required?

With cavity sizes constantly increasing and people’s unease with successfully adjusting relieving angles growing every day, we started seeing Fero FAST brackets—sometimes referred to as “stand-off” brackets—on drawing sets for relieving angle attachment. When the industry realized this system also had advantages over traditional relieving angles for reducing thermal bridging, we started seeing them specified on most Passive House drawing sets and eventually some non-Passive House drawing sets as these high-performance details began leaking into other projects. Although they may present some advantages to labor in the field due to their adjustability, the additional material costs for the pieces supplied by Fero typically drive up the cost of the exterior wall over traditional alternatives. Halfen and others make a similar system to Fero, but Fero appears to be the most common.

Figure 16 — A typical Fero FAST Bracket

Are continuous bond beams shown in the CMU course below plank bearing really required or can the reinforcement at the slab edge do this structural work?

Some engineers show all required reinforcement for the slab edge in a bond beam below the plank bearing level and some show this within the area of the grout stop. The latter is less expensive because this area must be formed, reinforced, and grouted anyway. We are constantly questioning the former detail when we see it on drawings, but we have yet to successfully convince an engineer of our position who hadn’t already come to it on their own. Nevertheless, the hundreds of buildings we have built without a continuous bond beam below the plank bearing level are still standing…

Figure 17 — On the left, a standard plank detail from Denardis at New Roads Plaza (2 #5 bars in the grout stop). On the right, a detail from RGE at 985 Bruckner (2 #4 bars in the bond beam below the plank AND 2 #5 bars in the grout stops).

Is the requirement for rebar splice overlap length reasonable?

In bearing and shear walls, if the rebar splice overlap requirement specified by the engineer is too long, drastic increases in labor can be incurred in order to lift the CMU up over the top of the (comparatively longer/higher) rebar by hand. A #9 bar generally requires an almost 5’ lap splice—which results in masons having to lift the CMU basically to eye level and thread it over multiple rebar in each cell. This along with the overall reinforcement quantity should be checked on all load bearing masonry projects, especially at the shear walls. We have even seen engineers specify more reinforcement than can reasonably fit in the CMU cells—and more than once at this point.

Are anti-corrosive coating requirements for masonry reinforcement reasonable?

For example, many specification books will require hot dip galvanization for exterior and interior wire reinforcement but the Monadnock company standard is (at the time of this writing) only mill galvanization for interior reinforcement with hot dip galvanization reserved for exterior reinforcement only. (Some oddball specification writers will note stainless steel reinforcement which obviously should be avoided due to cost.)

Is the specified method for lateral support of CMU partitions cost effective?

Architects and engineers will often show “seismic clip” or brackets for lateral support at the top of non-load-bearing CMU partitions in their standard details. However, masons typically prefer, and it is typically less expensive to use partition top anchors (PTAs). (Obviously, load-bearing CMU partitions do not need lateral support.)

Figure 18 — A structural detail showing "seismic clips" on the left from Desimone and a structural detail shown PTAs on the right from Denardis. It should be noted that both of these engineers are typically open to a PTA substitution.

If atypical brick bonds are shown, are they indispensable to the overall design?

As is their wont, architects will often indicate a variety of special patterns or brick bonds. At the time of this writing, stack bonds seem to be on trend. This is one area where we can quickly save cost. Even though the piece count and material cost are the same with a stack bond and a running bond, stack bond brickwork is less forgiving for deficiencies in workmanship (the alignment of the joint pattern calls attention to slight variations). For this reason, much more care must be taken with every brick and production rates suffer as a result. Lower production rates translate quickly to additional cost.

Figure 19 — Stack bond brickwork at 985 Bruckner.

Are grouting requirements and procedures reasonable?

Structural drawings and specifications will often outline very specific grouting and grout inspection requirements for reinforced CMU. This language must be reviewed carefully because it is often out of step with actual field masonry standards.

Are all the testing protocols for the masonry façade reasonable?

More and more frequently, testing protocols are elaborately specified by owner consultants. These requirements may be in in Division 01 sections related to sustainability, Division 04 sections related to masonry, or Division 07 specifications related to the AVB itself. Typical (and onerous) requirements we see in specification books include exterior hose testing or chamber testing of the exterior AVB. (This is still relatively uncommon in practice compared to site window testing.) Although often the costs of testing itself are borne by the owner, the requirements can nevertheless add to construction costs if they interrupt the flow of work and reduce productivity rates.