Case study – poor workmanship in an aluminum shingle roof install, investigated in 2008.

We were asked to diagnose a case of roofing materials being damaged by sliding snow and ice.  The covering materials were made from Interlock Finall aluminum shingles.  The company that carried out the installation was “no longer in business”.  While carrying out the inspection, I witnessed many elements that I considered substandard, and workmanship which was quite appalling.  The photograph documents one location where a number of deficiencies were found.

Example of poor detailing on an aluminum roof install.

Example of poor detailing on an aluminum roof install.

The area in the photograph is the lower part of a roof, adjoining a wall.  The correct approach would have been to do this part in the following manner:

  1. The sidewall flashing is removed.
  2. The old roof covering is removed.
  3. A base flashing (about 4”x4”) is installed the length of the roof-wall join, and waterproofed with roofing cement.
  4. Water-proofing membrane (ice-and-water-shield membrane or other peel-and-stick membrane) is installed along the roof/wall joint, running about 4” up the wall, and extending past the eve by about 1-2”.  To ensure adhesion to the metal base flashing and the brick, the area is first primed with roofing cement.
  5. A width of water-proofing membrane is installed along the eave, with about 1-2” of membrane extending past the eave, to protect the upper portion of the fascia board.  The membrane is 36” wide, so the eave is covered by membrane along the eave to a height of about 34-35”.
  6. The rest of the roof surface is covered by synthetic underlayment, to provide cover for the roof until the covering is installed, and to provide a water-proof barrier to any condensation that will occur under the metal surface after installation.
  7. A starter flashing is installed along the base of the eave, to provide an attachment point for the shingles, and to ensure water cannot enter the roof system.  If there is a gutter, the membrane need to be BEHIND the gutter (ie, between the gutter and the fascia board), and the fascia portion of the starter flashing should be OUTSIDE the inner gutter wall, so the water is directed into the gutter.
  8. A side-wall or end-wall flashing is installed along the roof-wall to a) provide a solid attachment point for the shingles, b) to prevent water entry, c) provide a drainage path for any water entering the join at that point, and d) to create an esthetically-pleasing transition detail between the roof and the wall.  The vertical height of the flashing is usually determined by the amount of expected snow accumulation, with the top being ideally at least an inch or two above the expected snow height.
  9. At the join of the endwall flashing to the starter flashing, the endwall flashing is placed OVER the starter flashing so that any water carried by the endwall flashing is directed to the outside.
  10. The shingles are installed, locking into both the starter flashing and the end-wall flashing.
  11. A wall counter-flashing is installed over the top of the end-wall flashing, to ensure that the wall-flashing join is protected from the sun, wind and water.  Depending on the wall material, the counter flashing is positioned into a cut (if brick), or is custom-fitted to follow the contours of the brick or other material.

This photograph documents that many of these steps have not been done.

Step 1 (remove old flashings) – was done.  This can be seen by the residual caulking (greyish in colour) that was left on the brick.  Note that the original counterflashing was fitted to follow the brick grouting.

Step 2 (remove old roof covering) – not done.  We can see the old roof covering (green asphalt shingles) peeking through at “H”.

Step 3 (install base flashing along wall) – not done.  We should have seen the base flashing at the corner of the roof/wall at “H” if it was there.

Step 4 (install waterproofing membrane along roof/wall join) – not done.

Step 5 (protect eave with waterproofing membrane) – not done.

Step 6 (install underlayment) – unknown.

Step 7 (install starter flashing along eave) – done, but poor finishing detail.  The flashing should have extended to the wall, but instead it was cut short leaving the roof/wall/fascia corner completely unprotected (“I”).

Step 8 (install endwall flashing) – done, but poorly.  The endwall flashing (running up the wall under the counterflashing), is cut short at the base (see “G”), and does not overlay the starter flashing.  It also does not go up the wall high enough to prevent water entry if water-saturated snow has accumulated on that roof section, and the flashing itself does not appear to have a internal safety bend that would keep the water in a channel.

Step 9 (lap endwall flashing OVER starter flashing) – not done.

Step 10 (install shingles) – done.

Step 11 (install counterflashing along wall) – done but poor workmanship and detailing.  There was no attempt to “marry” the flashing to the brick.  The counter-flashing was poorly bent (see “C” – edge of bent is not crisp and straight, so it appears this was done by hand), the flashing was effectively glued to the wall with caulking (see “B”), with two fasteners holding it to the wall (see “A” and “E”) causing buckling (see “D”).  The counter flashing should have extended past the end-wall flashing at the eave, but was terminated much earlier (see “F”).

Because of the many short-cuts taken, water entering the gutter can go and enter the fascia board at “J”.  It can be also seen that the gutter is loaded with ice in winter, and has been deflected downwards (see the break in the old caulking at “K”).

The point of this analysis is to show that the pesky little time-consuming details matter in giving a good end-result.  Giving the illusion (appearance) of having metal installed without paying close attention to the details, is not sufficient when protecting the roof and related structures against the elements.

(c) 2014 Paul Grizenko

Which products are suitable for DIY roofing?

The two most common materials for DIY roofing are asphalt shingles and steel panels.

Asphalt shingles are pretty easy to install – as long as you follow the instructions on the package, nail in the right place, ensure the right off-set, and install the appropriate flashings (usually NOT described on the shingle package).  Of course, in addition to the shingles, you need to think about the underlayment, the waterproofing, allow enough heat on the roof to “seal” the shingles to each other, and as mentioned before, use an appropriate flashing for each roof termination or join.  People get the shingle nailing part ok, but often forget the rest of the details (those are not described on the shingle package).  Steeper slopes or windy areas require additional measures that are usually skipped.  In addition, the shingles aren’t going to last very long – we often replace roofs that are anywhere from 10-15 years old.

Metal roofing CAN be relatively straightforward to install, if the roof is not too steep and is not complicated with valleys and skylights, and similar features.  However, there are different systems, and each system has its own peculiarities.  Let’s start with a sampling of products, and see what aspects you need to consider.

The cheapest and simplest roofing to install are steel panels such as you see often on barns and sheds.  These are sold through hardware stores, and are usually called “screw-through” roofing, because they are fastened to the deck using screws that go through the metal.  Some manufacturers require strapping under the metal panels, others don’t.  They feature relatively shallow ribs that run down the vertical direction of the panels.  Flashing details tend to be rather rudimentary, and rely on caulking for waterproofing and foam blocking to prevent insects from entering under the roofing panels.  Since they are designed to be cheap, the paint quality used on them is not very ultraviolet (UV) resistant, and often fades or bleaches in 15-20 years.  The zinc coating tends to be thin and you can see these types of panels rusting from the ends in as little as ten years.  The screws seal against moisture entry using a rubber or neoprene collar or washer, but these are also affected by UV and lose their sealing ability after 10 years or so.  For these reasons, I am not a fan of this type of product.  Depending on the thickness of the metal, some panels show the effects of snow after a few seasons, in the form of deformations or indentations in the metal between the furring strips.  These panels are better than asphalt shingles, but not by very much.  By the time the panels get to be 20-30 years old, they are usually replaced because of the poor appearance, or the rust, or the leakage at the screw-holes.  On the plus side, they are a cheap and fast way to cover a barn or shed.

A much better system is one using locking panels which have standing ribs with the fasteners hidden under the overlapping panels.  These also use various ways of locking panels to the trim and flashings, so that there are no exposed edges.  However, because these panels require bending to make the locking parts, they usually require specialized tooling for cutting and bending.  Some homeowners have the ability to do this level of work, but for most, this level of technical execution is reaching the limits of their ability.  Consider also that if your roof requires panels in excess of 20 ft., it becomes quite physically challenging to lift such a panel onto the roof and position it correctly.  Therefore, although hidden-fastener vertical steel panels are a much better choice compared to the barn roofing described earlier, both the skill level and the tooling required make it more difficult for the DIY installer.

A much easier product for DIY installation is the metal shingle.  These come in several forms and materials – steel, aluminum, copper, zinc, and stainless steel.  The surface finish can be natural, galvanized, painted, or granulated.  The shapes can be square, rectangular or diamond-shaped, and can feature various surface textures or profiles (wood grain, smooth, slate, shake, or stone).  The most common products of this type are painted steel shingles, and painted aluminum shingles.  The shingles vary in size from relatively small rectangles (9” high x 18” wide exposure) to much larger ones (18” high x36” wide).  While the details vary from system to system, in general they all rely on a system of flashings for every roof joint and protrusion.  These flashing form the foundation for the systems, with the shingles effectively just filling in the space between the flashings.  So with these systems, the emphasis is not on the roof covering (that’s the easy part), but on the correct choice, placement, and positioning of the various flashing elements.

The role of the flashings is actually quite complex.  Depending on the flashing type, they provide a hidden water channel to drain rainwater away, and/or they provide barriers to water entry, and/or they provide a secure attachment point for the shingles, and/or they are the primary means to resist wind uplift, and/or they provide a safe channel for sliding snow or ice, and of course, they have to look good.  Therefore, up to 50% of the effort on a metal roof is associated with the installation of the flashings.  The problem however, is that most suppliers of DIY materials don’t do a very good job explaining which flashings are used where, what are the safeguards you’re supposed to use, and how to ensure that the flashings are properly installed.

Of course, it is also not a good thing to install the flashings first, and then install the shingles – this approach ends up directing any water in the flashings under the shingles.  So part of the installation process is the interleaving of shingles and flashings to direct the water to the outside.  Again, this is almost never explained by the vendors of DIY roofing, and yet it is a critical component of a well-designed system.

The easiest product to install for the DIY roofer is usually the aluminum shingle.  They are relatively small,  very light, and the metal is easy to cut and bend.  Since aluminum doesn’t rust, that means the product will last a very long time.  With the right paint system on the surface, a good appearance should last 20-30 years or more, and the shingles themselves will easily last over 100 years.  However, since the shingles are made from a very thin metal, the roof preparation becomes very important to get a smooth, strong, waterproof surface that can provide proper support for the shingles.  Painted steel shingles are somewhat harder to work with, as the metal is much stiffer, so both cutting and bending is more difficult.  Granulated steel shingles are usually NOT a DIY project as they require special cutting and bending tools which are designed to cope with the granulated coating.

Because metal roofs made from shingles and flashings have many potential entry points for water (every joint is a potential entry point), it is important to understand the principles and techniques that minimize these entry points.  Furthermore, a prudent installer considers additional lines of defence against water infiltration in the form of waterproofing membranes at all penetrations and other potential leak points.  If the surface is slippery, thought must also be given to how the snow and ice will behave on the roof, and whether there are any obstructions that can catch ice and snow.

Therefore, for DIY permanent roof installation, the most common material used is the aluminum shingle system, followed by the hidden fastener vertical steel panel.  However, the two keys to a successful installation is a proper match of the materials used to the roof and to the skills of the installer, and the proper roof preparation that minimizes the potential issues.  We’ve worked with over 80 homeowners all over North America who have done this successfully.  Contact me to find out how to join this happy group.

(c) 2014 Paul Grizenko

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

So you want to DIY (do it yourself), but CAN you? Should you?

The answer to this question comes from the four “A”‘s:  Ability, Agility, Attitude, Aptitude.  Each plays a role in making it possible.

You’ve decided that you want to do the roofing yourself, and you are prepared to do the necessary learning and training to do it right.  However, another aspect to consider is your physical ability.  Roofing work requires some strength, good balance, and the ability to work in weather conditions that may not be ideal (either hot, or cold, or windy).  There are times when, due to rapid change in weather, you have no choice but to continue working even as the conditions deteriorate, and you have to have the ability to do so.  Roofing and renovation is physical, sometimes demanding work.

Roofing work also requires agility and awareness of your position in space.  You need to easily move from scaffold or ladder to the roof and back again.  If you’re working on a roof platform on a steep slope, it may require a little bit of physical effort to position yourself next to the work area.  Physical agility is important.  During the course of a single full working day, you may be up and down the scaffolding or ladder at least 30-40 times, usually carrying stuff up or down at the same time.

Some DIY projects can be done easily by one person.  Roofing usually requires at least two sets of hands, unless you are doing a very simple and low roof installation.  Even something as simple as running a chalk-line goes much better/easier with two people working together.  If you have to re-deck, it is much safer to have two people manipulating the sheet into place.  If there is a lot of measuring and cutting involved, it is often much simpler to have one person on the roof doing the measuring and another on the ground doing the cutting, bending, etc.  Installing a 10-ft. piece of flashing on the rake almost always requires two sets of hands.  Putting up or taking down the scaffolding is much, much easier with at least two sets of hands.

Roofing work can also be dangerous.  If getting up on a footstool makes you dizzy, you may want to reconsider.  Things can slip out of your hands and bounce down the slope and to the ground.  Sometimes you can trip on a safety rope or a piece of material.  On some materials, the footing can be very slick and you can slip.  Working on high ladders can be very dangerous if the ladder footing is not solid, or the ladder is not anchored properly at the top.  Therefore to work safely on a roof, requires a mindset that safety is always first.  Remember Murphy’s Law?  Don’t give Murphy an opportunity to play his game.  Accidents usually happen when someone doesn’t pay attention enough to everything that is going on around them.  Distraction is a common reason for the lapse in attention.

In some ways, despite the nature of the work being rather physical, the main indicator of success will be the mental attitude the installer takes on the project.  Your aptitude to plan the project, consider the risks and how you will handle them, take the time to learn the skills on the easier parts, check yourself as you go, work purposefully and carefully, will all contribute to your success.  “Measure twice, cut once” fits here.  As does “Haste make waste”.  

Next Post :  Is your roof a candidate for DIY?

(c)  2014 Paul Grizenko

DIY (Do-it-yourself) because knowing is important.

Some people go the DIY route, because they want to learn more about that aspect of their home, or that acquire a specific skill set.  They want to know what makes a system work well.  They want to understand the strengths and weaknesses of various products.  And they want to learn what it takes to do the work properly.

I’ve had some people who were teaching themselves everything involved in building a house, and they were quite meticulous about learning the principles, the options available to them, the techniques underlying the installation process, and the ways to look for weaknesses or failure points.  When it came to making their roofing choices, they took their time (one couple took a full year before they went ahead with the decision to do it themselves), and took the recommended training to ensure they had everything done right.  They invested in the good-quality tools and they were very careful about their preparation.  I have found these people an absolute joy to work with – they ask a lot of questions, and if they don’t understand something, they keep on asking questions until they are satisfied that they have it figured out.  In the end, they get stellar results.

If you want to DIY for your roofing project, and you fit this profile, you will almost certainly have a very good result.  Call us to find out what parts of the plan you need to have in place, and what information you will need before making this decision.

Next Post:  You have your reasons for DIY – but can you?

(c) 2014 Paul Grizenko

When DIY (do it yourself) is the option because you can’t find anyone to do it for you…

You can use the information in the articles “How to get a good quote for your roof”, and “How to choose a contractor in Quebec”, to get ideas of how to get the right contractor to do your project.  You’ve met the reps from several companies and you’ve had a look at the work being done by the crews.  After watching how they work, you’re left with the uneasy feeling that they are not as professional as the rep was saying.  At the very least, you wouldn’t want them on YOUR roof.

You may also be in a place where getting help is difficult (at a cottage, or on an island).  Maybe the time when you can get access to the job site is not convenient for other people.  Or it is difficult to coordinate your schedule with that of your hired help.  Whatever the reasons, sometimes it’s just simpler to do it yourself – at your own pace, and on your schedule.

If that is your situation, deciding whether a DIY installation is appropriate will require planning things and determining what would be a realistic and do-able scenario.  If you’re not sure, give us a call – there is a process to be followed, and it’s a lot easier when working with someone who’d done this many times before – like us.

Next post:  DIY so that you can learn.

(c) 2014 Paul Grizenko

Quality – a good reason to do it yourself.

If you ever watched a really good roofing crew at work, you’ll note a number of things about them:

  • They are not hurrying, but are moving purposefully.
  • Everything seems to be progressing in a clock-work manner.
  • The workers are properly secured and are using the right tools.
  • The work trailers or trucks are neat and well organized.
  • The work site is reasonably clean
  • There’s not a lot of loud yelling and running around.
  • The work is continued until done.
  • If bad weather happens, the team is prepared.

However, if you watch a more “average” crew, you’ll see some of the following:

  • Some are working very hard, others are barely moving
  • There’s a lot of yelling
  • Working materials are all over the place
  • The workplace is a mess (and stays a mess at the end of the workday)
  • The work trailer/truck is a mess
  • The workplace feels like a “Jackass” movie set
  • The work is done intermittently – with absences of days between activity (maybe due to visits to the hospital?)
  • No one is in charge (the anarchy model) or one person is doing all the directing (the dictator model).
  • There doesn’t seem to be a clear logic to the work being done (waddasyamean, the waterproofing is UNDER the shingles?  Hey, who knew?).

Do you see the pattern?  The first group knows the sequence of work, uses the right tools, work in a safe way, and are prepared for the unpredictable things.  They work as a team.  The second does not have the experience or knowledge of how the work should flow, or just don’t care enough.  They work as a bunch of guys who need a job.  Which group do you think will give the higher quality?

So why isn’t everyone using only the first team?  Good teams usually cost more than the average teams – sometimes a lot more.  Good teams are not common – you need to search to find such well-functioning teams.  And sometimes, the good teams are not available when you need them because they are fully booked.

You can take your chances on the more common “average” team – but how will you know they did a proper installation?  You don’t know – there are just too many places where short-cuts can be taken.  Pride of workmanship is often missing from the “average” team – partly because they are being paid a minimum wage to throw the product on the roof.

If you want it done right, and if you want to be really sure, then the alternative is to do it yourself, IF you are prepared to acquire the knowledge, practice the skills, and do the work in a safe and careful manner.  It helps to have a coach or mentor keep an eye on things and point out potential problem areas.  If you want to do this, give me a call – I’ve worked with quite a few people over the years to ensure their DIY project was planned and done right.

Next Post:  When DIY is the option because of lack of available labour.

(c) 2014 Paul Grizenko