Roof Inspections

A fundamental activity in assessing the status of a roof is a thorough inspection.  Unfortunately, too often, it is not done, or done poorly by the roofing salesman, or the roofing representative or an inspector.  This is partly due to lack of knowledge/training, and partly due to attitude.  So, what should you expect to see or learn from a proper roof inspection?

The first thing to consider is that the roof is part of the house’s external envelope, and as such interacts with the rest of the house.  The house construction depends partly on the time when the house was built, and the building codes in effect at the time, and partly on the design/construction choices that were made.  Many older homes have also had renovations and “improvements” done to them, not always by qualified people, and not always taking into account the way these changes affect the rest of the house.

Other factors that affect the way the overall system functions include the living habits and lifestyles, the location of the house relative to its environment, the current prevailing climate, and the degree and type of vegetation around the property. 

Inspections therefore serve to reveal the “ground truth” of a home’s construction, quantify to a degree how the various components interact, and reveal the deficiencies and weaknesses.  With this information in hand, it is then possible to determine which changes are necessary, and to prioritize them if they cannot all be done at the same time.

Why isn’t this done all the time?  Homeowners usually don’t do this because they lack the knowledge, experience and (sometimes) the ability to conduct an inspection.  Home inspectors (particularly the ones who give a checklist inspection at very little cost) usually are generalists, and are focused on the current state of the home, and not necessarily on the cause-and-effect.  Salesmen often don’t do this because it can be dirty work, they don’t have the knowledge about the things that can go wrong, and in any case, their job is to make a sale of product or service, not to play consultant. 

What should you expect from a good inspection?  While the answer depends on the house, the objectives of the inspection, and the intended use of the inspection information, the list below covers some of the aspects:

  • Assessment of the roof covering, penetrations, seals and flashings,
  • Assessment of the decking/sheathing condition and structure,
  • Assessment of the insulation type, distribution, effectiveness and condition,
  • Assessment of the ventilation function, quantity, distribution and effectiveness
  • Determination of the way the snow behaves on the roof in winter
  • Determination of the way the water run-off works,
  • Assessment of the effectiveness of the vapour barriers
  • Determination of issues of condensation, inappropriate venting, and insufficient sealing against air movement

As part of the above list of areas to cover during the inspection, it is also necessary to understand what one is seeing.  When is 12″ of insulation more than adequate, and when is it grossly insufficient?  Why is having lots of large Maximum vents not always the perfect solution to ventilation issues?  When is a roof with curling shingles in better shape than one with the shingles all lying flat?  When is an ice-dam a reason to worry, and when can you safely ignore it?  What is the significance of rusty-looking nails protruding through the sheathing?  It is relatively common to find overlapping deficiencies that amplify the effects.

Sometimes, it is not possible to access all parts of the roof system, and it becomes necessary to do “exploratory surgery” to establish the facts of the physical reality.  This is often the case when a problematic portion of the roof is hidden due to the way it was constructed, or because it was sealed off to prevent a careful inspection.  The latter is a red flag.  I remember one particular situation when I was hired by a young couple to check the state of the roof of their newly-purchased home in an older part of town.  The renovations done by the previous owner did not allow access to the attic or any cold spaces.  When we succeeded in gaining access, we discovered the insulation completely covered in black mold.  Upon getting our report, the owners did some further investigation (removal of portion of a gyproc wall in their newborn daughter’s bedroom) and found the entire wall space covered with mold.  It turned out that the history of the building was not disclosed to the buyers and the seller was “flipping” the property after acquiring it for almost nothing.  The new owners had to move out and pursue redress through the courts.

Other types of issues we’ve seen during inspections, is the problems that putting in additions or extensions without fully understanding the operation of the “system” can cause.  Typically, when a cold space is converted into a heated, four-season space, there is not enough thought put into how the insulation, ventilation and vapour barriers will interact.  This results in appearance of condensation in places it was never present before, in the transfer of heat to the roof that was not a problem in the original structure, and in various other symptoms.  When the new owners are trying to rectify the surprising deficiencies, they often find that the money spent on the repairs is wasted, as the root causes of the deficiencies were not addressed.

Most people buying an older home do not have an unlimited budget to rebuild it to meet all the current requirements.  Therefore, having a good inspection is important to allow effective evaluation of which issues are critical, which are important, and which can be lived with.  From this assessment, it is then possible to develop a phased approach to addressing the issues in a systematic manner.

Why can’t you get the inspection done as part of a “free estimate” advertised by many companies?  You might get lucky and get a knowledgeable roofer (not a salesman!) who will take the time to understand your situation.  Chances are however more likely that you will get a “consultant” or “representative” who is there to sell you a roof.  Their first, second, and third priority is to make the sale, and to use whatever justification they can find to win your trust and persuade you to agree.  Since most companies have a “primary advantage” of some kind over the competition, that becomes their solution to any issue you may have (when all you have is a hammer, then everything looks like a nail).  Their solution may address part of the problem, but not necessarily all the aspects.

Doing a good inspection is necessary to establish the cause-and-effect, the weaknesses, scope of work, the priorities, and the sequence in which the work should be done.  It usually requires much more than a 15 minute walk around of the property.  Everything that the inspector sees or notes, should be documented with photographs, and quantified by measurement. For instance, in a recent consulting engagement, the homeowners were told by an inspector that the insulation was “good”.  After my inspections, we were able to determine that:

  • The insulation varied from 8-10 inches of cellulose fill over old fiberglass insulation in one part of the roof (the client had contracted for 12″ of fill over the vapour barrier),
  • The insulation was blown into the soffit cavity (thereby obstructing the air intake from the soffits)
  • The insulation in another part of the roof was equivalent to only 6″ of fiberglass (giving at best about R18, instead of the desired R40), and the insulation in that part was not packed effectively, severely reducing the effectiveness of the insulation that was there.
  • The quantity and quality of insulation in a newish extension was unknown as that entire area was not accessible, but suspect from the quantity of ice damming occurring.

After the inspection, the inspector should be able to show the images of deficiencies found, and explain what should be the desired state, and how much of a discrepancy is shown between that state and the actual state.

If you’re in the greater Montreal area and want to have us do an inspection for you, please use the contact page to send us a request for such a consultation.  If you’re further afield, but want to have a detailed check list, use the contact form to give us your contact coordinates.  I’ll then call you to determine if we can help you, and if so, which form this help can take.

I’d love to hear of your experiences with inspections.  Use the comment link to make the comments on this page. 

(c) 2014 Paul Grizenko

One thought on “Roof Inspections

  1. Pingback: Planning for a new (re-) roof? A checklist of things to consider. | PRS Consulting

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