Can your roof be done the DIY way?

Another aspect to consider whether the DIY route is appropriate for you, is the roof you plan to work on.  If it is a single-story, simple, walkable bungalow, with minimal roofing features, it will be straightforward.  If it is a multi-story, steep, complicated roof with many dormers, transitions, and protrusions such as skylights…  it won’t be.  That’s not to say it can’t be done – but it will require a much more careful planning from the installer.

Have a look at the sketch of a relatively simple roof.  Not too high, not a lot of complications.

House schema

True, there is some steepness.  But what else do you need to think about?  Here’s the same sketch showing some of the places where things can go wrong.

House schema Trouble spots

A – Chimney flashing
B – Ridge
C – Hips
D – Gables/Rakes
E – Valleys
F – Endwalls/sidewalls
G – Eaves
H – Below dormer

Not illustrated:

I – Transitions
J – Curved roof sections
K – Unequal starters
L – Skylights
M – Plumbing vents
N – Ventilation vents
O – Steel tubular chimneys


When things go wrong, they rarely happen on the flat areas with the shingles.  That’s not where the various forces that affect the roof get concentrated.  To engineer a system that is effective, you need to think about the various ways failure can happen, and for each failure mode, provide an appropriate countermeasure, with backup.  Each problem spot in the above diagram has specific challenges.  For instance, the endwall/sidewall (F) is responsible for waterproofing that joint, for channeling water driven in that direction by wind, for keeping out the meltwater that occurs when a snow mass is pressed against the warmth of the wall, and for anchoring the shingles at that perimeter.  The traditional weaknesses of the endwall flashing occur at the junction with the soffits at the top edge of the dormer, and at the lower part where it intersects the eave or joins the roof surface.

Other areas, such as the ridge (B), have other challenges, mainly related to wind, and wind-driven water.  Therefore the flashing system should properly anticipate the probable failure mode at each location and have the appropriate way of minimizing or eliminating the dangers in that area.  The installer must then ensure that the installation properly integrates the design elements so that all no weakness is introduced.

So far, we’ve been discussing the installation of the roofing products.  The preparation of the roof is just as important, yet is the area where many DIY-ers (and most roofing companies, unfortunately) skimp.  As discussed in other posts, the roof is a system, which starts with the vapour barrier, and includes the insulation, the ventilation, the decking, the underlayment, the flashings and waterproofing, and finally, finishes with the roof covering.  There is not much point in delivering a top-quality covering when the rest of the system is functioning poorly, as those deficiencies will affect the performance of the roof.  For example if the insulation is poor, then the there is a great potential for ice-dam formation, and related leakages.  Similarly, if the vapour barrier is not functioning well, then there is a good possibility of condensation with consequent rot of the decking or other roof components.

Besides the technical aspects, there’s also the issue of time.  It takes a significant time investment to study, learn the necessary skills, do the required preparation, and then carry out the installation.  Since most people considering DIY roofing have other jobs and obligations, it is common to see the project be done in sections or stages, since it is rare for people being able to do such a project without stopping.  If your roof has sections that can be worked on independently from the rest of the roof, this makes your planning and doing that much easier.

Another aspect is the location and access.  If, for example, your roof is on your cottage which requires several hours of travel to get to it, it is obviously very important that you have everything you need to do any aspect of the work with you – again planning is the way to ensure that nothing gets missed.  The access to the roof may require additional equipment, such as scaffolding, very long ladders, and even manlifts.  So the feasibility of doing it yourself should consider how easy or hard it will be to get to the roof in a safe and effective manner.

Roof preparation, debris disposal, and the amount of repair work, also will affect how quickly you can do the project, how much help you need to arrange, and what preparations you will have to make to ensure that things don’t go wrong.

We usually recommend a thorough inspection, careful measurement, and some thinking about the objectives of the exercise.  Some home-owners we work with go for a metal roof solution because they want a reliable, durable and high-performance covering that they will need to do only once.  However. not all roofing products are suitable for DIY installation.

Certain products require special tooling and skilled labour.  Others can be installed using commonly available tools, and are relatively easy to handle single-handed.  The roof complexity can also force the choice of product, since some products are very laborious to install on complex roofs.

Therefore, we suggest a consultation to ensure that the product that is being considered is appropriate for the installation, your skill level and ability, and the environment in which it will be installed.

Which brings us to the next post:  How does the product’s characteristics affect its use for the DIY project?  Tune in to find out!

(c) 2014 Paul Grizenko

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