Dark Gypsum Kalamazoo 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.

Milhiem Masonry
(616) 485-3740
1102 4th St Nw
Grand Rapids, MI
 
Dunritebrick
(586) 738-7498
42356 Parkside Cir
Sterling Heights, MI
 
All Pro Masonry
(586) 868-3860
4778 Dunkirk Ct
Sterling Heights, MI
 
Debacker & Sons
(586) 775-8700
21750 Schmeman Ave
Warren, MI
 
Stone Doctor
(248) 698-3161
White Lake Twp
Sterling Heights, MI
 
Hanneman & Fineis Concrete Construction Inc
(517) 371-4053
16101 S US Highway 27 Ste 6
Lansing, MI
 
Able Concrete Inc
(517) 371-4855
1305 S Cedar St Ste 105
Lansing, MI
 
DAVE BUHLER MASONRY INC
(810) 639-1887
PO BOX 363
FLUSHING, MI
Services
CHIMNEY AND MASONRY REPAIR

R J Masonry
(517) 455-0099
1535 Linval St
Lansing, MI
 
Kennedy Masonry Inc
(517) 322-9310
6554 Sloan Hwy
Lansing, 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.

Click here to read full article from Masonry Construction