Dark Gypsum Warren MI

The construction is 4-in. brick masonry walls with 4-in. concrete masonry backup. The interior has light gauge steel hat channels attached to the concrete masonry with rigid insulation between the channels.

Debacker & Sons
(586) 775-8700
21750 Schmeman Ave
Warren, MI
 
Builder Mike
(586) 446-4640
11193 E 13 Mile Rd
Warren, MI
 
Marcel Construction
(586) 757-8392
26242 Grobbel Ave
Warren, MI
 
K C Masonry And Concrete Impressions
(586) 795-9401
6345 Product Dr
Sterling Heights, MI
 
Stone Doctor
(248) 698-3161
White Lake Twp
Sterling Heights, MI
 
A Ct
(586) 772-1660
25530 SchoenheRR Rd
Warren, MI
 
Expert Construction Co
(586) 293-0920
31056 Shawn Dr
Warren, MI
 
Silverado Construction Inc
(586) 758-2600
2055 E 9 Mile Rd
Warren, MI
 
Unique Pools & Masonry
(586) 610-9939
33567 Ryan Rd
Sterling Heights, MI
 
Giannola Masonry Co
(586) 792-2070
35086 Cordelia St
Clinton Township, MI
 

Dark Gypsum

Provided By:

Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: November 1, 2008

By Norbert V. Krogstad

What causes the dark vertical lines that occur on gypsum wallboard installed directly over the furring strips in brick veneer/concrete masonry walls?

The construction is 4-in. brick masonry walls with 4-in. concrete masonry backup. The interior has light gauge steel hat channels attached to the concrete masonry with rigid insulation between the channels. There is a vapor barrier over the insulation and hat channels. The gypsum wallboard is anchored to the hat channels on the interior face of the vapor barrier.

We were originally thinking that the problem was associated with leakage through the masonry. However, the building has large overhangs and during most rains the water doesn't even get to the brick masonry. Also, the vapor barrier would stop any moisture that did get in the masonry from reaching the interior wall board anyway.

How can this problem be avoided?

The darkening of the gypsum wallboard over the hat channels is sometimes referred to as “ghosting.” This phenomenon is typically caused by condensation from interior air during cold weather.

Because the insulation was placed on the interior side of the concrete masonry, both the concrete masonry and brick masonry are cold. The hat channels interrupt the insulation and are in direct contact with the cold masonry walls.

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