Indoor plastic film dehumidified structures.

TM 38-260

(2) If the decision is made to build a hutment as opposed to buying one commercially, the following steps can

be used as a guideline in the construction of the structure. These guidelines are for a pipe supported style hutment, but

some of the general information can be used to build other types of structures.

(a) Overhead cold water pipes shall be removed or insulated to prevent condensation in hot weather and

the resulting accumulation of the condensate on the hutment roof. Roofing requiring major repair or replacement within

approximately 2 years shall be repaired before hutment installation. Sources of excessive drafts shall be repaired or

modified to prevent tearing of plastic film.

(b) Seams. Wherever feasible, procure a sheet of polyethylene large enough to cover the entire hutment.

If this is not possible and the material must be joined together to provide a cover of sufficient size to cover equipment and

provide for trim allowance, the seams shall be heat sealed and have strength characteristics equal to 80 percent of the

parent material. The seams shall be continuous on the inside of the cover and free of holes, skips in welds, or burned

through spots. The seams shall be continuous on the inside of the cover, so that after erection, resealing of the seams

will be possible.

and equipment entrance. This entrance shall consist of 2 zippers, installed vertically in the side wall of the plastic cover

with the open end flush with the edge of the blanket. A pull tab will be located on the outside of the plastic wall. The

length and location of the zippers shall be specified by the procuring agency. The base plate and screws between the two

zippers shall be removable for hutments with a wood base. Sandbag sealed bases can be opened up anywhere along the

sandbag sealed hutment walls; therefore, it is not necessary to install a personnel and equipment entrance (see

paragraphs f and g below).

(d) Ordering information. The procuring agency shall supply the dimensional data for the hutment to

include the trim allowance around the hutment as well as the location of the equipment entrance zippers. (See fig 5-4. )

The polyethylene blanket shall be fabricated of 0. 006 inches (6 mil) thick clear polyethylene of the widest widths practical

for the hutment size.

(e) Preconditioning of flooring. The floor area to be occupied by the hutment shall be preconditioned

wherever practical to overcome openings and cracks in the area within the hutment. Irregular levels around the perimeter

must be corrected. All cracks in the floor within the hutment shall be wire brushed and sealed with hot asphalt. A sealer

coat can be used to prevent moisture coming through the concrete where concrete is prone to moisture permeation.

Equipment pit openings, floor drains, and other openings shall be effectively closed and sealed when the equipment is not

to be laid-away in place. Areas under the machines located in place will not be seal coated. The procuring agency shall

specify the extent of seal coating.

(f) Installation of the base plate. The floor area around the perimeter of the base plate location shall be

cleaned and wire brushed. The joint for the base plate shall be made by troweling a heavy coat of asphalt compound for

the full width of the base plate around the entire perimeter of the space to be occupied by the hutment. The base plate

shall be secured to the floor

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