Quonset insulation fills tricky gaps

System protects | It is a combination of products and a strategy to provide airflow that keeps condensation from forming

MOOSE JAW, Sask. — Quonsets once used to store farm equipment don’t measure up on many of today’s farms.

Equipment has simply become too large to fit through the doors of the older, corrugated steel half-circle buildings.

However, this doesn’t mean the buildings are past their useful lives.

A Moose Jaw company has a way to insulate these buildings so that farmers can heat them and use them as shops or offices.

H.B.T. Enterprises is the Saskat­chewan distributor for Quik-Therm Insulation, an expanded polystyrene that is bendable and filled with air rather than gas such as extruded polystyrene.

Vic Tuplin of H.B.T. Enterprises said there are several obvious challenges to insulating a Quonset: the buildings are round, ridged and tend to rain inside because of condensation.

“We use a wood structure, using the existing bolts and tying two-by-fours horizontally on the structure, sort of like hanger wire,” he said.

“Between the two-by-fours we are putting 1.5 inch insulation.”

A two inch layer of insulation is then added, which covers the two by four strapping and adds more resistance to stop thermal bridging. Thermal bridging occurs when wood acts as a conduit for heat loss.

The second layer is attached to the strapping with screws and washers. The joints are all foamed and taped, and then a low profile cladding can be installed. The cost for both the 1.5 inch and two inch insulation is $2.50 per sq. foot.

Venting is key to the process. Tuplin said most farmers deal with condensation problems in Quonsets by opening the doors and allowing temperature and humidity to equalize.

Keeping the steel under the dew point in an insulated building requires airflow, so installers will cut four inch holes 10 feet apart in the outside lower wall of the Quonset and place screen venting over the hole. Whirlybirds on the roof draw the air through the vents and up the space between the wall and the insulation.

This keeps the temperature consistent and prevents the dew point from forming, which typically occurs at 2 C and 30 percent humidity.

“You have to keep that metal under the dew point,” Tuplin said .

The R value of the Quik-Therm product is 25.

Farmers may have tried to use spray foam to insulate Quonsets, but Tuplin said there can be leaks around the metal bolts and washers. As well, freeze-thaw cycles mean the building can’t dry out.

Spraying is definitely less labour intensive.

However, the steel buildings are galvanized, and the protective coating has to be removed so that the spray foam will adhere.

“Over time, it’s not a friendly thing,” Tuplin said.

Farmers might also consider that new national building codes coming into effect next year mean the interior of any commercial insulated buildings must be covered. Tuplin said this could affect what farmers choose to do, depending how they intend to use former Quonsets.

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