Sample project

Warehouse TPO re-roof in Acheson

A 118,000 sq ft distribution warehouse with a failing roof, replaced in TPO while the building kept shipping.

Overview

The owner of a large distribution warehouse in Acheson needed a roof that would stop leaking over stored goods, installed without interrupting a two-shift shipping operation. This sample shows how a full TPO re-roof can be planned around a working building.

No lost shipping days

Phased work kept every dock door operating.

Wet insulation removed

About 22% of the old insulation was saturated.

Drainage corrected

Ponding between drains eliminated with tapered insulation.

Infrared scan of a flat roof showing trapped moisture

The problem

The original roof, a ballasted EPDM system from the early 1990s, had reached the end of its life. The tenant was logging leaks at a dozen locations each spring, most of them over the racking in the main storage area, and two leaks had damaged palletized stock. The property manager had paid for patch repairs for three years and wanted a straight answer: could the roof be recovered, or did it have to come off?

We started with an infrared survey at night, then cut core samples to confirm the readings. About 22% of the insulation was wet, concentrated around the drains and along the north parapet, where snow drifted every winter. That ruled out a recover. Moisture trapped under a new membrane keeps degrading the insulation and the deck, and it puts the new warranty at risk.

Old roof being torn off during a commercial roof replacement

The approach

We recommended a full tear-off and replacement with 60-mil white TPO, mechanically fastened over new tapered polyiso insulation and a cover board. TPO suits a building like this: a large, simple roof with few penetrations, where a white surface cuts summer heat gain over stored goods and hot-air-welded seams resist freeze-thaw when they are welded and probed properly.

The old roof drained poorly, with water sitting between drains for days. The new tapered layout, with crickets between drains, gave the whole roof positive slope to relocated drain sumps.

The warehouse could not stop shipping. We worked in sections, tearing off only what the crew could make watertight the same day, so no area sat open overnight. Hoisting was scheduled around dock traffic, with a traffic controller at the hoist zone during shipping hours.

The result

The roof was finished in seven weeks, two days ahead of schedule, with no lost shipping days. The first spring melt drained fully within 24 hours, with no ponding at the old problem areas. The tenant has reported no leaks since completion.

The warranty issued

At closeout the owner received a 20-year manufacturer NDL warranty and Rain's 10-year workmanship warranty, along with the as-built tapered insulation layout, detail photos and a maintenance schedule. The roof is now on our spring and fall maintenance program, which keeps the NDL warranty in good standing.

Scope of work