Our work

The details that separate a liner from a system.

Anyone can lay plastic on dirt. What separates a system is how the seams, the walls, the piers and the penetrations are treated.

A rendering of a technician seen from behind, kneeling on a new vapor barrier floor and pressing seaming tape down a seam that runs toward a wrapped pier

Fig. 1 Seams

Seam overlap and sealing

Laps of at least 12 inches, twice the model code, sealed with mastic and mesh on clean, dry plastic, and run upslope so water crosses a seam rather than entering it.¹

Fig. 2 Wall edge

Wall termination and fastening

The top edge of the wall liner is fastened with masonry screws through washers, over a bead of double-sided butyl tape, because tape or adhesive alone will not hold. Run full height, it stops 5 inches below the floor joists to leave the termite inspection gap.²

Fig. 3 Piers

Pier and column detailing

Each pier gets its own wrap, at least 4 inches up the column and 12 inches out onto the floor, so the floor sheet laps over a flap instead of being slit around a post.³

Fig. 4 Penetrations

Penetration treatment

Every pipe, duct and wire through the sheet gets a patch cut with an X, slid over it and taped down as a collar.⁴

A rendering of an untreated crawlspace floor before the work: wet red clay, loose stones, a sagging insulation batt and torn old plastic along the walls

Before the sheet

The floor is cleaned, cleared and graded before any plastic goes down.

Vegetation, organic material, wood scraps and rubble come out, and so does any old plastic, because covering it traps water and debris where mold can grow. Standing water is a stop: drainage first, liner second.⁵

Loose insulation hanging from the joist bays is rehung as part of the job, priced after the inspection.

Before and after

Wet clay and standing water, then a sealed floor and a fastened wall.

Water on a crawlspace floor is a drainage sign, and it is solved before the sheet goes down. Drag the handle to compare the two.⁶

Fig. 5 Before and after

Drag, or use the arrow keys

See what happens after you get in contact

Free inspection

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About an hour under the house, then one fixed price. Texts are answered right away.

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(919) 928-2847 Text us [email protected]