Flat Roof Replacement 
A guide to membrane, assembly and design choices.

With Significant Experience our Red Seal Journeymen Staff are Experts at Commercial, Industrial, and Residential Flat Roof Replacement.

Residential and Commercial Repair and Replacing Flat Roofing Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Vancouver, Whistler, Winnipeg, Toronto and points between. Alberta, British Columbia, Saskatchewan, Manitoba, Ontario.

Flat roof re-roofing on residential, commercial, industrial, multi-family and institutional complexes.

About Full Flat Roof Replacements (Full Removal)Replacing a Flat Roof  A guide to membrane, assembly and design choices. Red Seal Journeymen Experts.

Definition of flat roof replacement or full removal of the roof system.

A complete flat roof removal or replacement is the process of our crews fully tearing-off the complete flat roof system right down to the structural deck (or the “substrate”) and replacing the old flat roof system with a brand new system from above substrate and up. 

Tearing Off the Complete Roof Can Have Benefits

Although there are obviously additional costs associated with “tearing off” a complete flat roof system, re-roofing in some instances will deliver the longest life-cycle for your new roof. This isn't always the case, in many instances whether a roof replacement or a recovery the life-cycle is the same. The only way to determine the life-cycle difference is to consider various scenarios of installation specification and the affect each decision will have on roof longevity.

On example of a key advantage of complete roof replacement over recovery is that the flat roofers at GRS are then able to inspect the system right down to the deck (or substrate) when all the materials are removed. At which time (when the full stripping is done), or roofers can are then able to make any needed repairs to the substrate or roof assembly and structure. This is valuable if you are concerned about rot. We can also do significant core testing in advance which would alleviate any concern.

All-in-all, for the most part, there are solutions or methods to execute a roof recovery so that a roof recovery can be just as successful as a complete re-roof.

Product ChoicesCommercial, Industrial, Residential. Calgary, Red Deer, Edmonton, Fort McMurray

When considering a variety of commercial and flat roof membranes, you will ultimately be choosing from the following primary flat roof product groups:

1. Multi-Ply Conventional Built-Up (BUR - Tar and Gravel).

2. Two-Ply Modified Bitumen. SBS typically – torched on usually. Sometimes mopped on and there are also cold-applied systems.

3. Single Ply - TPO or PVC (White Reflective Cool Roofs) or EPDM (Rubber Roll-On Roofing - usually black in color but also comes in other colors).

4. Spray on Roofing Systems (Asphalt Spray On, Elastomeric Coating, Liquid Rubber, or Spray Foam - SPF)

5. Metal Roofing. Metal roof owners also have the option of applying a coating such as an Elastomeric Liquid Applied System (a reflective coating) or some other form of roof coating to waterproof their metal roof (e.g. liquid rubber). 

It is important to remember that flat roof product choices are more about what will perform properly given the type of building, the location of your building and type of use than it should be about preference or price. When it comes time to choose the right membrane ask your rep at GRS to review the trade-offs with each type of flat / low slope membrane.

About Recovery Systems (Retro Fitting or Recovering an Existing Roof)

Definition of a flat roof recovery vs. complete replacement.Lloydminster, Lethbridge, Medicine Hat, Canmore, Red Deer, Alberta, Saskatchewan, AB

A Flat Roof Recovery System (recovering a roof) vs. a complete flat roof replacement is when an additional roof system is installed on top of an existing system. This adds another complete covering to your existing roof system. (Calgary Flat Roofing project shown in photo to right). 

There are a number of considerations when designing a successful long-term flat roof recovery (overlay) system. Some of which are as follows:

1. Weight Load. The ability of your existing building structure to handle the additional dead-load to the flat roof. Most modern structures can easily handle a second system. However, older structures or if adding a third or more systems can be problematic. Check with a structural engineer.

2. Moisture. Making sure that existing moisture in your existing system is considered.

As required, our roofers will perform a moisture scan of your existing roof to ensure it is a suitable substrate for an overlay. If there are only limited areas of saturated insulation it may be beneficial to simply cut out those specific areas instead of removing the whole existing system. This saves on costs and also the existing roof system then doesn't enter the landfill.

Once checked for moisture and weight load, any surfacing is removed (such as the gravel on the top of a tar and gravel system) and then a layer of insulation or fiber board is attached to the existing roof and directly into the structural deck (typically mechanically fastened but may required gluing).

Once there is an appropriate roofing surface for our roofers to work on there are a variety of membrane options that can be installed.

3. Slope and Drainage. Determining whether added slope or drains are required.

A primary consideration with recovery systems is the roof drainage. If your current roof system is pooling water then doing a straight recover will do nothing for that problem. What you see now is what the pooling of water will look like after the roof recovery is completed unless you add sloped insulation.

An alternative is to add internal drains or external scuppers that terminate water off the side of the building in to downspouts. Internal drains can be costly and can pose a placement problem below in the building.

Also to consider is that when adding sloped insulation you also then need to add parapet wall height which can be costly as the cap flashing and any other exterior fascia flashing will need to be replaced also.

Similar to a full removal (as above), when recovering an existing roof you will be choosing from the primary membrane materials: Conventional Built-Up (Tar and Gravel), Modified Bitumen Built-Up (SBS), Single-Ply (PVC, TPO, and EPDM), Spray On (Spray Foam, Liquid Rubber, Asphalt Emulsion) and Metal.

About Metal Roof Restoration Services (Coatings)

Metal Restoration Systems provide property owners (typically done on Commercial and Industrial buildings) the opportunity to extend the life of an existing metal roof using a Liquid Elastomeric Coating, Liquid Rubber or some other form of coating specific to the required need. Commonly applied with a combination of spray equipment or squeegees, brushes, and rollers, sophisticated engineered coatings work with the various dynamics of the existing metal system.

Membrane Choices - Do Your Research

We believe an educated customer is the best customer. Researching each of the system costs and the contractors is a smart thing to do. Depending on your existing roof structure and plans for use of the flat roof area, this will have an affect on your flat roof replacement choices.

For example, if you have a metal deck, you are going to need to design a lightweight system when replacing or restoring the roof. Or, if you have a substantial amount of equipment mounted on the roof or lots of foot traffic or are using it as a rooftop deck, you will need to examine systems that are tough and puncture resistant.

Expert StaffCranbrook, Kelowna, Vancouver, Whistler, Saskatoon, Regina, Saskatchewan, BC, MB, Ontario

One key advantage when communicating with our staff is that we install every commercial and residential flat roof system type. Our staff are extremely knowledgeable and unbiased - we don’t just install one or two types. We can provide you with system information from the most respected sources and manufacturers for you to make an educated selection. (Our Calgary AB Roof Replacement staff are shown in the picture). 

Quotations, Roof Observation Reports and Proposals

Our proposals include; quotation details, references, workmanship guarantees, specification details, various system options, various ways to roof the system (re roofing, overlay, coatings, etc), photographs of your existing system, photos or diagrams that show the various steps associated with installing the new system, and cross-section sketches as you may be required to illustrate the components or details. 

To connect with an expert staff member call +1.877.497.3528 or email us at info@grscanadainc.com.

For a Free Estimate or further information online Click Here.

Related Links: 

Roof Systems Available  |  Design Considerations  |  Specifying a Re-Roof  |  Rooftop Decks  |  Green Roofing  |  Commercial Roof Considerations  |  EPDM  |  TPO  |  PVC  |  Tar and Gravel  |  Torch On SBS Modified  |  DecTec  |  Spray Foam 

Roof Replacement Contractors, Calgary Flat Roof Replacement, Calgary Flat Roofing, Red Deer, Edmonton, Fort McMurray, Lloydminster, AB, Saskatoon, Regina, SK, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Whistler, BC, Winnipeg, Toronto, and Vancouver Flat Roofing, Flat Roofing Alberta, British Columbia, Saskatchewan, Manitoba, Ontario.
(Photos are Calgary Commercial Roofing and Edmonton Commercial Roofing crews hard at work).

General Roofing Systems Canada (GRS)