Flat Roofs

FLAT ROOF MATERIALS

There are a variety of materials used for low slope applications. Data compiled by Western States Roofing Contractor’s Association, in the July/August 2011 Western Roofing magazine indicates the following percentages of material types installed for new roofs:

TPO – 18.2%
Built-up Roofing (tar & gravel or cap sheet) – 17.9%
Modified Bitumen (SBS) – 12.5%
Modified Bitumen (APP) – 9.9%
EPDM (rubber) – 9.4%
Liquid Applied (urethane, acrylic, asphalt emulsion) – 8.6%
PVC – 3.5%
Polyurethane foam – 2.3%
Other types (steep slope) – 17.7%

Installation and method of repair varies with material type. Diagnosis, repair techniques and material ‘basics’ are as follows:

1. Surface should be dry and clean for all types.
2. TPO: Re-weld; weld a patch; apply EternaBond type material; Chemlink sealant or comparable.
3. Built-up roof: Apply asphalt adhesive and/or asphaltic mastic, and/or modified mastic or urethane extended asphalt with reinforcing fabric.
4. Modified bitumen SBS: Same as built-up roofs.
5. Modified bitumen APP: Same as built-up roofs and/or weld seam(s).
6. EPDM: Apply EternaBond type material or re-glue seams, or glue patch of EPDM, or apply Chemlink sealant or comparable.
7. Liquid Applied: Urethane – reapply urethane; Acrylic – reapply acrylic or apply urethane extended asphalt and reapply acrylic; Asphalt emulsion – Apply asphaltic mastic or urethane extended asphalt.
8. Polyurethane foam: Apply urethane extended asphalt and/or acrylic.

The diagnosis of a leak in order of probability is the first step in the process of elimination.