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Affordable. Durable. Professional Roof Replacement

To many, the thought of replacing a flat roof is daunting. If you own one building, it’s probably something that you’ve never had to do before. Even if you own many buildings, assessing roofs, life expectancy and costs can be intimidating considering the potential financial repercussions of an incorrect choice.

“Northern Seal makes the process as simple for you as possible.”

We will never recommend a roof replacement that we don’t feel is necessary so you can be easy knowing that driving up the cost of a job is never our goal. We believe that a simple cost-benefit analysis for your roof should always make the correct option clear.

First, take the cost of your roof, for example, $20,000. A roof should easily last 15-20 years, so take 20 years. Divide 20,000 by 20 and you get $1,000 which is the yearly cost of your roof.

If repairs are costing you more than the yearly cost of the roof then it’s about time to think about roof replacement. If repairs are still under that price then you should still be investing in the old roof.


When you replace a roof there are generally two options; going over the existing roof or stripping the old roof in order to lay a new one. Which one of these choices is best will depend on a few factors: weight considerations, the state of the roof decking materials and the presence of mould, sagging or other concerns.

The most cost effective option is going over the old roof, however, sometimes because of previous damage this is no longer an option. This is one of the reasons it is important to keep on top of repairs to your roof, to prevent damage to roof decking which then leads to more costly roof repairs.

Roof Over – Advantages
  • Cost effective
  • Fast.
  • Seals easily each night.
Roof Over – Disadvantages
  • Adds weight to the roof.
  • Not appropriate for all applications.
  • Can make it hard to locate leaks.
  • Should not be done more than once.

Full Strip – Advantages
  • Cleaner.
  • Reduces weight.
  • Easier to locate problem areas and repair decking.
  • Often required before a solar installation or other project.
Full Strip – Disadvantages
  • More costly.
  • Takes longer (we have to be more careful of rain).
  • Harder to seal each night.

Choosing between a full strip and a roof over can be a hard choice. After inspecting your current roof, our project manager will be able to counsel you as to which option is best based on your roof and your needs.

We will Never Recommend an Unneeded Roof Replacement

Everyone knows that up-selling happens. This is when unneeded replacements, repairs and other work is recommended just to drive up the price of a job. Here at Northern Seal you can rest assured that we will never recommend work that we don’t believe is needed. To us it just doesn’t make sense.

If we recommend a new roof when repairs would have given you another three years, we’ve lost three years of a mutually beneficial relationship with you. We will do the repairs now and know that there is more work for us in another three years.

By building a relationship we will still be in your mind in two years when someone asks you about a roofer. We do good work and get a lot of referral business.

By working together to extend the life of your roof instead of re-roofing and walking away, you save money and we get more business. It just makes common sense.

Debris Chute for Safety

When doing a full strip of an old roof it is important to ensure the safety of the building and any other nearby assets such as cars and adjoining properties.

For this reason we have a chute system to guide debris into proper receptacles, instead of having stone, tar and roofing products simply thrown off of a roof. This prevents risk to people and property and also keeps the work site, your building, looking clean and organized.


When re-roofing, even when installing over an old roofing membrane, we recommend rigid-foam insulation. This product reduces heating costs and makes the building more energy efficient and eco-friendly.

When roofing over a previous roof it also provides a separation layer between the roofing membranes which separates any materials which can negatively affect performance from your new roofing membrane.

All roofing products rely on specific chemical formulas and knowing which ones work together and which react negatively with each other is one of the reasons working with a flat roofer is so important.