Tuesday, March 6, 2012

Low Slope Roofing - Shingles, Metal, Low Slope Roof Membrane

Low Slope Flat Roof & Metal Roof
Low Slope Roof Shingles, Metal, and Roof Membranes
What You Need to Know

General Roofing Systems Canada (GRS) is a Roof Repair and Replacement Contractor Serving Alberta, BC, and Saskatchewan. Low Slope Roofing Shingles, Metal, and Flat Roofing Calgary, Red Deer, Edmonton, Fort McMurray, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Vancouver, Whistler, and points between.

How to Choose Low Slope Roofing

When re-roofing low slope roofing systems it is important to be sure you are using the right material for the right roof slope, local building code, and roof material manufacturer specification.

Below we provide a guideline for low slope shingles, roof membranes of flat roofs, and metal roofing.

Malarkey Shingles
Low Slope Roof Shingles

Serious consideration is required when you are considering re-roofing a roof that has a roof slope that is less than a 4/12 pitch (or slope).

For roofing with a 3/12 pitch regular shingles can usually be installed with 2 ply 15 lb roofing felt paper as underlay (check with your specific building code and the shingle manufacturer).

The General Roofing Systems Canada (GRS) specification for how to install roofing shingles is to never use felt paper (we use ice and water protector on eaves, valleys, around chimney flashing, etc and we use synthetic roof underlay such as titanium). In this instance (with a 3/12 roof) I would consider seriously using only an ice and water membrane vs. the 2 ply of roofing felt. This is especially important around chimney flashing, skylight flashing, and any roof vents, valleys, and openings.

A roof that has a 2/12 - 3/12 slope is more tentative and the risk increases. Some shingle manufacturers such as IKO with the Cambridge shingle will warranty their shingles on a low slope roof for twelve years. And Malarkey shingles will honor a 30 year warranty on low-slope roofing.

A roof that is 2/12 or less in slope should have a "flat roof" or traditional "low slope membrane" installed. We like to see any roof that is less than a 4/12 slope get a low slope membrane that is fully adhered, mechanically fastened, or ballasted.

IKO Shingles
Other information:

Malarkey Shingle Installation Guide - Includes Install Instruction for Low Slope 2/12 - 4/12 pdf

IKO Low Slope Shingle Bulletin - Installation of Asphalt Shingles on Low Sloped Roofs pdf

IKO Roofing - Applying Asphalt Shingles on Low Slopes (covers 3 tab shingles, eave protection, etc) pdf

Our Article on this blog for residential re-roofing considerations with low slope roofs

and the follow up post on Low Slope Roofing on our blog.

Low Slope Roof Membranes (Flat Roofing)

Low Slope Roof
Low slope membranes for flat roofing come in a few categories;

1. Single Ply Membrane. Single ply membranes come in the form of EPDM (rubber), TPO (Thermal Plastic), or PVC (Poly Vinyl). Single membranes are either fully adhered, mechanically fastened, or ballasted.

2. Two Ply Membrane. The primary two ply membrane is the SBS Modified Bitumen that can be torched down or cold applied.

3. Built up Roofing. Built up roofing is another way of describing multi-layer roofing. An example would be the traditional tar roofs that are commonly referred to as tar and gravel roofs or flat-top tar roofs.

4. New Built up Roofing. More recently modern technologies have advanced the built up roof and newer built up flat roof systems have been introduced that utilize environmentally friendly products and modifiers vs. the tar or bitumen commonly used in tar roof systems. The newer versions of built up roof systems are extremely tough, will outlast almost any other roof (our opinion) and are VOC free making them perfect sustainable offerings to low slope roof assemblies. Tough Roof is an example of the modern built up roof systems as is the GRS Liquid Rubber Built up Flat Roof (a four layer voc free engineered liquid rubber flat roof with 800% elasticity and environmentally friendly synthetic fabric between layers vs. traditional tar felt paper.

5. Spray Foam Roofing

Low Slope Metal Roof
Low Slope Metal Roofing

Low slope metal roofing (steel roofing, roof cladding, standing seam metal roofing) has been used for decades primarily in commercial and more so even in industrial roofing settings.

With residential roofing, metal roofing is more typically found on steeper residential roofs. We install a lot of metal roofing at Mountain villages like Whistler, Squamish, Canmore, Banff, Cranbrook, Fernie, etc. We also do a lot of residential metal roof shingle installs in cities like Vancouver, Edmonton, and Calgary. More and more metal panel and metal shingle roof residential installations are growing, but the greatest volume of metal work is on industrial facilities by far.

At issue with metal roofing is that no other form of roofing material expands or contracts as much as metal roofing does. The seams between roof panels, the fasteners, roof openings at vents, chimneys, flashings, and skylights are expanding and contracting all the time. Ultimately, metal roofing leaks due to the expansion and contraction of the steel or metal.

Also, condensation with metal or steel roof systems can be an extremely frustrating situation. Many roof leaks with homes or businesses are actually not leaky roofs, they water coming through the ceiling is a result of condensation.

Dealing with the potential leak or condensation issues with metal roofing in advance of installing a new metal roof is key.

We solve the problem of metal roof leaks with installing a premium roof membrane under the metal roof system, we use a premium caulking tape at the seams, we like to use hidden fasteners, and if you really want to solve the potential of leaks or condensation water in advance... torch a SBS modified membrane or spray liquid rubber in advance of putting the metal roof on.

For commercial roofing and industrial roofing that already has a metal roof on that is leaking, typically we will coat the roof with liquid rubber and it will be good for another 10 years or more. Trying to locate metal roof leaks and deal with them in an isolated way is not usually a good investment of time. Click here to visit the roof coating section of our website.

Any questions you have for roof repair or replacement give us a call at +1.877.497.3528, email us at info@grscanadainc.com, or click here for online request form.

Low Slope Roofing
Until next time,

The Team at GRS


General Roofing Systems Canada (GRS) is a Roof Repair and Replacement Contractor Serving BC, AB, SK. Leaky Roof Repair Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Vancouver, Whistler, and points between.


Calgary Roofing

General Roofing Systems Canada (Calgary)
240 - 70 Shawville Boulevard SE
Suite 1460
Calgary, Alberta Canada
T2Y 2Z3
+1.403.873.7663 Service
+1.877.497.3528 Toll Free
+1.403.387.0318 Calgary Shop
+1.403.617.9803 Project Manager Direct (Mobile)

Calgary Shop:
76 – 4807 32 Street SE
Calgary, Alberta Canada
T2B 2W1

Edmonton Roofing

General Roofing Systems Canada (Edmonton)
3428 99 Street NW
Edmonton, Alberta Canada
T6E 5X5
+1.780.424.7663 Service
+1.877.497.3528 Toll Free
+1.780.800.4947 Project Manager Direct (Mobile)

Edmonton Shop:
3 - 12916 156 Street NW
Edmonton, Alberta Canada
For deliveries call in advance.

Vancouver Roofing

General Roofing Systems Canada (Vancouver)
1489 Marine Drive
West Vancouver, BC Canada
V7T 1B8
+1.604.261.7663 Service
+1.877.497.3528 Toll Free
+1.604.800.4353 Project Manager Direct (Mobile)

For roof repair or replacement in other areas of British Columbia, Alberta, or Saskatchewan click here for our roofing service regions or call +1.877.497.3528.

Article topics; Low Slope Roofing, Low Slope Shingles, Roofing Shingles, Low Slope Metal Roofing, Metal Roof Leaks, Leaky Roof, Membrane, Malarkey Shingles, IKO Shingles, Roof Repair Calgary, Edmonton, Red Deer, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Vancouver, Whistler. AB, BC, SK