How assumptions lead us astray

“If others tell us something we make assumptions, and if they don’t tell us something we make assumptions to fulfill our need to know and to replace the need to communicate. Even if we hear something and we don’t understand we make assumptions about what it means and then believe the assumptions. We make all sorts of assumptions because we don’t have the courage to ask questions.”

― Miguel Ruiz,  The Four Agreements: A Practical Guide to Personal Freedom


We can’t live without them.  That’s just a fact of modern life.  We can’t possibly fact-check everything we come across, or hear, or read.  So as a convenient short-cut, we make assumptions that allow us to move onto whatever it is we’re trying to do.  If those assumptions were wrong, then most of the time, it’s usually not a big issue, as we probably didn’t make life-altering decisions based on those wrong assumptions.

Assumptions are the ground upon which we build the structure of our thinking.  Just as most times you don’t probe the ground in front of you before taking a step, you don’t check every bit of information about something before thinking about it, or making a decision, or taking an action.  Most of the time, that’s perfectly fine, because we’re usually in familiar territory and we’ve passed this way and that way many a time without any negative consequences.

When we venture into new areas, we need to be a bit more careful.  Unfamiliar territory “may” be just like what we already know, or it may not.  If it is not, then how will you make sure that it is safe, or that you are making the right decisions?  How do you know that the “rules” in this new place are the same that you are familiar with elsewhere?  The reality is that you don’t know.  And making the wrong assumptions can start having serious consequences.

What does all this have to do with roofing?  Lots, as it turns out.  Roofing is a field of expertise that is alien to most homeowners.  Dealing with contractors, especially if you’re doing it the first time, is also a form of altered reality.  When we get called to figure out a problem, we start by finding out the situation beforehand, what was requested in the contract, what was delivered, and how the result differed from expectations.  As we peel away the various layers, we almost always find that at the base, the problem started with the wrong assumptions being made, which then allowed the wrong decisions, and wrong actions.  We have traced unsatisfactory results to assumptions made by homeowners, by the contractors, and by the workers.  Even inspectors are not immune to this type of fault.

What are the assumptions that lead us astray?  There are, unfortunately, many.  The ones below are probably among the more common, however the list is definitely not exhaustive.

A.    Assumption:  Buying a roof (or renovation) is just like buying a product like a car or a fridge.

Ah.  A very common assumption, which could be true IF all homes were constructed in the same way, had the same history, had the same environment,  were used in the same way, and were installed to the same standard.  However, the roof is not ON the house, but is PART OF the house, and interacts with various elements in the structure.  Since every home is somewhat different, the way the roof needs to be built and integrated with the rest of the structure is different for each situation.  When you add to this the differences in the performance expectations that the homeowners may have, then it should be obvious that doing a re-roofing project is much more involved than just replacing the roof covering.

Another common fallacy is that the specs are sufficient to make a decision.  When you compare products, you usually get the specs and compare them – what’s the performance, fuel efficiency of energy efficiency, operating costs, capacity, etc.  However, the specs for a reroofing project are usually much more poorly defined.  If you are relying on contractors to tell you what needs to be done (as part of the “free estimate”), you actually have no clue about what they will actually deliver, and if they have determined what needs to be done in a thorough and correct manner.  If you don’t know which questions to ask, then you also do not know if your needs expectations (whether expressed or not) will be met.

It’s should therefore not be a huge surprise that the estimates can vary all over the place – and the assumptions made by the contractors are also not explicitly identified, so the “real” scope of work that will be done is very variable.  In fact, when comparing estimates, we often find that the price for doing the visible part of the work (putting on the roof covering, for instance), is very close, but there is wide variation in the preparation and detail work.

If you DO want to make the comparison of quotes consistent, then YOU have to give the bidders a comprehensive spec which identifies the work to be done in detail, and references the products and quantities that are to be used.  This spec is known as a “Request for Quotations” document, and identifies exactly what your expectations are.  This is common for commercial work, but unusual for residential installations.  And yet, without this kind of information, how do you know what you are buying?

B.    Assumption:  The marketing information is accurate.

We all love poring through the nice shiny advertising brochures, looking at the attractive models and locations, and imagining ourselves having some of that good fortune.  Of course, there’s a little game being played here – we’re being invited to project ourselves enjoying the benefits of the services or products.  To help us in this fantasy, to allow us to rationalize it to ourselves, the advertisers list the various attributes that should allow us to agree that this product or service will deliver.  This is known as marketing copy.  It is, if done properly, very seductive and persuasive.

However, we all know that in real life, we don’t usually get only the benefit.  There are trade-offs, side-effects, compromises, and other consequences that don’t get mentioned in advertising copy.  Where do we find out about those?  That’s where the hard work of research has to come in.  Some of the ways to verify advertising claims include:

  • Reading the warranty or guarantee information, and most importantly, the exclusions,
  • If test results are being quoted, then looking up the tests done, and understanding under which conditions the test results are applicable,
  • Checking reviews by (hopefully) independent sources,
  • Seeing actual performance of products over time.

In other words, we need to find out under which conditions the marketing claims have the possibility of being realistic.  Otherwise, we’re just buying into a really nice fairy-tale, and expecting the “living-happily-ever-after” to happen to us.

C.     Assumption:  The warranty is there to protect me.

Or course it is.  That’s why it’s written by lawyers hired by the company supplying the product or service.  That’s why it’s written in easy-to-read fine print, and in easy-to-understand legal language.  That why there are clauses saying that the warranty is in effect only if the product is used as intended by the manufacturer.  And of course you will ONLY use it in the way it was intended, and ONLY under the conditions under which it is warranted.

Warranties, when referenced by advertising, are in fact marketing documents.  They also are a legal limitation of liability by the company, intended to keep their obligation to the consumer/user of the product at a minimum level.  They can’t totally escape all obligations – our various laws prevent for the most part that kind of escape, but they can limit the consequences to themselves.

There is a class of warranties that are wonderful to read in the scope of benefit they promise.  However, keep in mind that the warranty is in effect only as long as the specific entity that issues the warranty exists.  Therefore the most generous warranties are written with the expectation by the issuer that they won’t be in business when the warranty claims start pouring in.  Those companies that DO stand behind their warranties are usually very careful to limit their liability to ensure that they can deliver on the promises made.

However, stuff sometimes happens even to the best companies.  When those companies disappear, or get bought out, the warranty promises evaporate.  It turns out that the best warranty is the knowledge that the product or service is well built or delivered, and that there is no need for a warranty claim in the future.  When it comes to roofing, the best warranty is a contractor who knows what he or she is doing.  Which brings us to the next assumption.

D.    Assumption:  The contractor knows what he or she is doing.

This is a natural and normal assumption.  After all, the company wouldn’t be in business if they didn’t know their trade, right?  That’s true for the good contractors.  However, the fact that they are in business doesn’t mean they are good, just as the fact that a person is breathing and alive doesn’t make them a “good” person.

So how do you know if a contractor knows what he or she is doing?  There are ways to find out.  I’ve covered much of this in the article “How to choose a Contractor (in Quebec)”.  However, it is also important to know that the workers or subcontractors also know their trade, and that is where most people fail to dig deeply enough.

Another aspect of this assumption, is that the contractor also has a degree in mind-reading, and knows what your expectations are even if these are not voiced or written down.  If the expectations ARE fully expressed, it is an assumption that he or she will understand exactly the same thing you are meaning (if you doubt that, then you were never married or had a close partner).

Therefore, when the work is under way, it is very important to check in periodically with the contractor, or the crew chief, or the foreman to verify that what is being done DOES conform to your expectations.  If they know what they are doing, they’ll have no problem explaining what, how, and why they are doing something.  If they can’t or won’t explain, then that’s a big red flag.

E.     Assumption:  The contract doesn’t have to cover every detail, because it’s obvious what has to be done.

As was noted in the previous section, what is obvious to you may not be obvious to the contractor, and vise versa.  A good contract should clearly identify all the work to be done, and just as importantly, put limits on the work being done.  This is to avoid “mission creep” when the original project morphs into something else.  This is a particular problem with longer projects, and it can be both very expensive, and very frustrating to all concerned.

We notice that the preparation and repair work often gets a minimum of discussion, if at all, and yet this is where the biggest discrepancies often are found, between what is done, and what should have been done.  On some projects, the prep work can be equal to or even more than the cost of the “main” work.  Since good preparation is the foundation on which the rest of the project is built, skimping on it almost always leads to unsatisfactory results.  And yet, it almost never gets properly discussed and described in the contract.

F.     Assumption:  The building structure is fine.  We checked one part and it should be the same everywhere.

If the original inspection was done in a cursory manner, then this assumption can wreak havoc on schedules costs, and effectiveness of the result.  As noted earlier, a re-roofing project is the blending of the old with the new.  If the insulation is good in one area, but poor in another, you can’t use the same approach in both.  How this gets resolved depends partly on the type of contractor you have.  The good ones will bring the “surprise” discovery to your attention, and propose one or more ways to change the scope of work to accommodate this discovery (at additional cost, of course).  The unscrupulous ones may either use this as an excuse to really jack up the price (especially if they won with a very low bid), or they can pretend that there was no surprise, and work as if it wasn’t there.  In the latter case, you’ll have the surprise down the road, when things aren’t working as they should.

This comes back to the point, that the best way to prevent this kind of surprise is to do a thorough inspection before starting the project.  If there are areas that are hidden, they should be opened up and explored, especially if those areas have been linked to problems.


It has been said, that wisdom to make good choices comes from experience, and experience comes from bad choices.  The smart person learns from the bad choices of others.  So, be smart, hire us to help you define what needs to be done, and put together a plan to make it happen.

© 2014 Paul Grizenko