Committee on Architecture for Education

This message has been cross posted to the following Discussion Forums: Committee on Architecture for Education and Technology in Architectural Practice .
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We have been asked to VE a building from a brick veneer with CMU backup to a single wythe split face CMU exterior wall system. My question is what is the best way to insulate and keep out or control moister in this wall system? ------------------------------------------- David Reed AIA Tulsa OK -------------------------------------------

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Dale Jerome AIA
French Associates
Rochester MI
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When we have utilized single-wythe CMU on educational projects, it has always been as a last resort to meet budget. We have utilized a foam injected (core-fill) insulation on these wall types. We have also specified integral water repellent in both the CMU and the mortar.

There also some weep systems for single-wythe masonry that utilize essentially a drain pan that sits at the bottom course of the wall.

Refer also to the NCMA publication TEK 19-2B "Design for Dry Single-Wythe Concrete Masonry Walls".

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Rodwell King Assoc. AIA
GPD Group
Akron OH
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Original Message:
Sent: 04-20-2012 08:51
From: Dale Jerome
Subject: Single wythe CMU exterior wall contruction



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Dale Jerome AIA
French Associates
Rochester MI
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When we have utilized single-wythe CMU on educational projects, it has always been as a last resort to meet budget. We have utilized a foam injected (core-fill) insulation on these wall types. We have also specified integral water repellent in both the CMU and the mortar.

There also some weep systems for single-wythe masonry that utilize essentially a drain pan that sits at the bottom course of the wall.

There are single whythe products that are designed for this application.  We are currently using a product called NRG blocks by Anchor that are designed with a weep system and thermal break to separate the exterior from interior.  We are using it on a beachfront project and the block we specified has an R-24 value.  Using standard blocks, I agree that it isn't a practice I would recommend for a use other than storage. 

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Michael Mark AIA
Mark Design Studios Architecture, PC
Hicksville NY
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Original Message:
Sent: 04-23-2012 07:10
From: Rodwell King
Subject: Single wythe CMU exterior wall contruction

Refer also to the NCMA publication TEK 19-2B "Design for Dry Single-Wythe Concrete Masonry Walls".

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Rodwell King Assoc. AIA
GPD Group
Akron OH
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Make sure to review your local energy code requirments for new construction.  Current 2009 Energy Code requires the use of continuous insulation at all conditioned areas.

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Robert Nicholson Assoc. AIA
Corgan Associates
Dallas TX
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Original Message:
Sent: 04-23-2012 07:10
From: Rodwell King
Subject: Single wythe CMU exterior wall contruction

Refer also to the NCMA publication TEK 19-2B "Design for Dry Single-Wythe Concrete Masonry Walls".

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Rodwell King Assoc. AIA
GPD Group
Akron OH
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Emily Basham
Architect
Stephen Rankin Associates
Naperville IL
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Original Message:
Sent: 04-23-2012 07:10
From: Rodwell King
Subject: Single wythe CMU exterior wall contruction

Refer also to the NCMA publication TEK 19-2B "Design for Dry Single-Wythe Concrete Masonry Walls".

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Rodwell King Assoc. AIA
GPD Group
Akron OH
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Anthony Mc Dermid AIA
TAP Architecture
Oklahoma City OK
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DON'T DO IT.

If the building is intended to be habitable - DON'T DO IT.

No coating or ad-mixture or buttered joint can keep the water out.  If you practice in Oklahoma you know we get torrential horizontal rains driven by mighty winds.  So think power washer prior to checking with your insurer who will advise you DON'T DO IT.

And if you are not convinced give me a call - I'm in the book - and I'll arrange to send you several boxes of very persuasive documents.

If the project is in the Mojave - disregard message. 



Original Message:
Sent: 04-20-2012 08:51
From: Dale Jerome
Subject: Single wythe CMU exterior wall contruction



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Dale Jerome AIA
French Associates
Rochester MI
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When we have utilized single-wythe CMU on educational projects, it has always been as a last resort to meet budget. We have utilized a foam injected (core-fill) insulation on these wall types. We have also specified integral water repellent in both the CMU and the mortar.

There also some weep systems for single-wythe masonry that utilize essentially a drain pan that sits at the bottom course of the wall.

Split face block is a very pourous material. Coatings are still coatings and to rely on them to keep the water out for the lifetime of the building is just a silly idea.
Single wythe construction should always have a flashing course at the base to catch any moisture. In a firm I worked for years ogo we did that for warehouses

Metal Structural Steel stud veneers systems are  workable with correct design, Correct drainage planes, correct air vapor barrier. You may get your cavity back
I prefer the insulation in cavity behind the veneer. If you put the insulation in the studs check your dew point!

If you use stucco make sure you have an enhaced drainage plane and not just the 15# felt.  3 coats systems are the best but are subject to workmanship issue.  Stucco is subject to damage/vandalism.

Good luck
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David DeFilippo AIA
Tsoi/Kobus Associates; Cambridge, MA
Milton MA
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Original Message:
Sent: 04-20-2012 08:51
From: Dale Jerome
Subject: Single wythe CMU exterior wall contruction



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Dale Jerome AIA
French Associates
Rochester MI
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When we have utilized single-wythe CMU on educational projects, it has always been as a last resort to meet budget. We have utilized a foam injected (core-fill) insulation on these wall types. We have also specified integral water repellent in both the CMU and the mortar.

There also some weep systems for single-wythe masonry that utilize essentially a drain pan that sits at the bottom course of the wall.

You did not state what the building in question is for.  A storage shed, bus barn, maintenance shop, or similar utilitarian structure might use a single wythe wall.  If this is an educational building, this VE suggestion sounds more like a recipe for a law suit.  I am skeptical about the possibility of constructing a building with such a system that would pass the energy code or keep out moisture.

The only constructive advice I can give for single wythe construction is to start the wall with a double wythe course that includes through-wall flashing.  This will help divert the moisture - that will most certainly enter the cores - to the outside.

I would counter with a different system, such as 6" metal studs, R21 insulation, gypsum sheathing, and faced with a combination of split-face block and stucco.  In such a system however, i would encourage you to spend a lot of time designing a good drainage plane behind the stucco, not just slapping it on against the sheathing.  This should save some money and still end up with a serviceable wall.

One final notion.  The worst mistakes I have ever made as an architect have come from trying to do something too cheaply.
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David Schele AIA
Felder Group Architects Inc
Austin TX
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