RESTORATION

Edinburg Post Office

Partial tear-off, sloped spray foam and coating

Project Overview

The Edinburg Post Office sits at 205 North Main Street in the town of Edinburg, in Shenandoah County. It is a one-story brick building on a corner lot, with about 3,500 square feet of flat roof.

The roof was holding water, and it had multiple layers of old roofing on it. The building needed a roof that would drain properly and stop the ponding.

Job Photos

Standing water across the post office's flat roof before the work (Edinburg Post Office, Edinburg, VA) — Standing water across the post office's flat roof before the work

Ponding water on the roof deep enough to reflect nearby buildings (Edinburg Post Office, Edinburg, VA) — Ponding water on the roof deep enough to reflect nearby buildings

Old roofing layer removed along the roof edge during tear-off (Edinburg Post Office, Edinburg, VA) — Old roofing layer removed along the roof edge during tear-off

Gray base coat being rolled over the new spray foam (Edinburg Post Office, Edinburg, VA) — Gray base coat being rolled over the new spray foam

Finished light-colored coating over the sloped foam roof along Main Street (Edinburg Post Office, Edinburg, VA) — Finished light-colored coating over the sloped foam roof along Main Street

Aerial view of the Edinburg Post Office with its new coated foam roof (Edinburg Post Office, Edinburg, VA) — Aerial view of the Edinburg Post Office with its new coated foam roof

The Challenge

Large areas of standing water sat on the roof, deep enough to reflect the houses across the street. Ponding water speeds up wear on roofing materials, adds weight to the structure, and finds any weak spot in the roof.

The roof also had more than one layer of old roofing. Building codes limit how many roof layers can be stacked, and old layers can trap moisture, so simply adding another flat layer on top was not the right answer.

Our Solution

We tore off one layer of the existing roof, then installed spray foam shaped to add slope so water runs off instead of sitting. We finished the foam with coatings. A gray base coat went over the foam first, followed by a lighter finish coat.

1We tore off one layer of the existing roofing.
2We prepared the roof surface and edges for the spray foam.
3We sprayed polyurethane foam, building it up to add slope toward drainage.
4We applied a base coating over the foam.
5We applied the finish coating over the base coat.

Why This Approach

Spray foam is one of the few roof systems that can add slope as it goes on. The applicator can build up thickness in low areas and taper it toward the drains or edges, so a flat roof with ponding problems ends up shedding water. Removing a layer first keeps the total number of layers in check and gets rid of old material that may hold moisture. The foam also adds insulation, and the coatings protect it from sunlight and weather.

Results

One layer of old roofing removed
Spray foam installed with added slope so water runs off
Base coat and finish coat over the foam
Clean, light-colored roof on about 3,500 square feet

Common Questions

How do you fix ponding water on a flat roof?

The fix is to add slope or improve drainage. Options include tapered insulation under a new membrane, adding drains or scuppers, or using spray foam, which can be built up in low areas and sloped toward drainage as it is applied.

How many roof layers are allowed on a commercial building?

Most building codes allow no more than two roof coverings, and some situations allow only one. If a roof already has multiple layers, at least some of them usually need to be torn off before a new system goes on.