Installing two roofs – why bother?

Most people assume that the visible external roof covering is the “real” roof, which functions to keep the water and weather out of the roof system.  This is true for flat or low-slope roofing materials, but not true for steep-slope materials (which is anything over a 3:12 roof slope).  Steep-slope materials are designed to shed water.  That means that water is supposed to run off the surface, and if properly layered, the water stays on the outside.  However, if wind or a physical obstruction interrupts the water flow, then it will go under the roofing material.  This is true for all steep-slope roofing material, whether it is made of asphalt shingles, or metal shingles, or metal panels, or cedar shakes, or slate.

It’s the unappreciated and unloved underlayment layer that’s below the top layer that has the job of actually keeping the water out.  That layer is the “true” waterproof roof, which is composed of layering of flashings, membrane, underlayment, and sealants.  It’s also the layer which is easiest to skimp on when the contractor is being pressed to come up with a low price.   If you can’t see it, and you don’t even know that it needs to be there, then why would you want to pay for it?

How does the saying go?  Ah yes.  Penny-wise, pound foolish.

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Tri-Energy – Update

After seeing the system presentation last year, and having had the endorsement from Jon Eakes, I considered adding the Tri-Energy system to my heating system, partly to get a better level of comfort, but primarily to reduce the overall cost of heating.

The system has been installed by Martin and his people, and we’re obtaining some experience with the operation.  I’ve chosen to have the Ecobee 3 thermostat (wifi-enabled) in addition to the electronic relays (some of the upgrades to the basic system).

We’re now starting to compile the usage data.

The basic system is a high-efficiency oil furnace as the primary system (distributing the heat through a central air ductwork), with the heat pump delivering the majority of the heating and cooling when above the critical temperature (of -12C). The Tri-Energy system added a third element (the auxiliary heating coils), along with the Tri-Energy controller and the EcoBee 3 thermostat.  The heating system also has a built-in humidifier.

We like to reduce the heat overnight, and raise it in the morning, so we have the thermostat set up with three settings:  night-time, day-time and “away”.  In the past, the older system would often sense that the heat needed in the morning is insufficient, and would switch to oil to raise the temperature to the target temperature quickly.  That would then generate a pulse of hot air, before the temperature would settle to the target temperature.

With the new system, the auxiliary heating coils kick in, eliminating the need for the oil heat for quick temperature increase in the morning, and the Tri-Energy controller modulates the amount of heating needed by the auxiliary heating coils so that the temperature rise is very even.   Of course, it does depend on how much heat can be delivered from the heat pump, so that there is more auxiliary heat needed on cold mornings (below 0C but above the critical temperature of -12C).

A recent innovation that Martin built into his system features a “pulse” feature on the oil heat.  The usual operation of the oil furnace is full-on until the target temperature is reached.  The new feature that Martin built in, pulses the oil furnace, so that it runs about 2 minutes on the burner, and then three minutes on the fan only.  Since oil usually generates a lot of heat, this heat then builds up in the ductwork, and by the time the hot air is moving into the living space, there is a lot of heat stored in the duct system.  With the new pulse feature, the running of the fan without the oil burner allows the air to run through the heated ducts, transferring some of the heat in the duct system, to the room air.

Compared to newer homes, we are still using more energy, and that can be traced to the lack of air sealing and insulation, something that we will have to improve over the next few years.  However, we have the benefit of much more even heat, and hopefully, lower operating costs over the years.


Unintended consequences – Renos that make ice dams.

That is a curious result that happens.  Someone finally invests some serious money in upgrading their kitchen (or bathroom), installing beautiful cabinetry, gorgeous ceiling lights, and finally get the attractive and bright kitchen (or comfortable bathroom) that they always wanted.  The following winter, an ice dam forms.  The following year, the ice dam gets worse and the ceiling starts to leak after every thaw.  What’s going on?

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Stripping is a good thing. Really.

Roof stripping, that is.  This is the process of getting rid of the old roof covering material, down to the deck.  In the process, if done correctly, you’ll learn a lot of things about what worked on your roof and what didn’t.  As all things that are good for you, there are costs and inconveniences involved, aspects which are exploited by those contractors who don’t have your best interests at heart.

What are some of the typical reasons you’re given why leaving your old roof on and going over is/are acceptable?  They include:

  • You’re saving money.
  • It’s more ecological (no landfill waste!).
  • It’s more secure.
  • It provides another layer of protection to your roof.
  • It’s recommended by the manufacturer.
  • There’s much less residual mess to clean up.

So many great reasons why you should just leave the old roof on, and go over!  And yet, pretty much all of these are false, based on the homeowner’s lack of knowledge of how the roof system is supposed to work, and compounded by the contractor’s desire to get the job done as fast as possible, get paid, and move on.  If you are presented with the suggestion that leaving your old roof on is an acceptable strategy, there are a number of things you should be aware of before you agree to this.

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Metal roofing -how to choose

Various roof failures, including asphalt shingle blow-off, and premature curling and cracking, has led homeowners to look for more reliable and durable solutions.  As such, people often start asking about metal roofing.

Metal roofing continues to be more and more popular, despite its initial cost, because people are getting tired of having roofs that fail much before their warranties expire.  The metal product offerings come in a dizzying variety of materials, appearances, textures, colours, and performance.  How does one wade through all the sales claims and marketing hype to decide which options are truly the best for you?  It helps to remember that there is no product invented by humans that is truly perfect in every circumstance.  So the exercise is to find the product whose weaknesses are minimized in your particular circumstances, and whose strong points are fully delivered.  It should not be a surprise that proper preparation and installation play a very big role in the final quality of the result.  So let’s examine a selection of products and discuss how their weak (and strong) points should be considered in your selection process.

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Spray Foam – good or bad?

Closed cell-spray foam used as insulation, has been on the market since about 1979, and has gone through a number of evolutionary steps.  The product is a solid plastic, formed by the chemical reaction of two primary components:  an “A” side which is isocyanate, and a “B” side which is usually a mixture of oils, stabilizers, fire retardants, blowing agents, and colouring agents.  The reaction is exothermic (ie, generates a lot of heat), and the materials form a solid within seconds. The blowing agents are the compounds which produce the low-conductivity gas that forms the bubbles in the foam, and thereby form the primary insulation.

When applied to a minimum thickness of 50mm (slightly under 2 inches), the material acts as  insulation, vapour barrier, and an air barrier.  Newly-installed foam has R-values of R-6 to R-7.5 per inch, but this diminishes to about R-5 per inch over time as the insulating gas dissipates.  Compared to other insulation products like fiberglass bat or mineral wool bats, the product has more insulating value per inch, and resists the loss of heating value that sometimes occurs with loose insulation due to air convection with extreme temperature differences.

The ability to prevent air and vapor movement is generally a good thing, except in situations where moisture can enter a wood structure, and then cannot get out.  Therefore the short answer to the question in the header is “spray foam is good when PROPERLY installed, and BAD when installed in inappropriate places or in an incorrect manner.  There are also issues of the impact on the environment, and potential impact on the health of the people living in the homes where the product is used.  The rest of the post touches on some aspects that inform whether the installation is good or not.

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Ice Dams – a look at remediation

February and March are usually ice-dam season in the Montreal area.  I’ve written before about ice dams What’s an “Ice Dam”?  and Ice Dams – Cures, fixes and band-aids.  and it’s time to look at what you need to do to make the problem go away.

The first thing to look at is the source of the problem, which is excessive heat transfer to the roof, the consequent melting of snow, and the freezing of the melt at the eaves and valleys.

This post will review the various components that contribute to the formation of ice dams, and will suggest a number of ways these can be corrected.

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The Stack effect and roof leaks

During the month of January, I’ve been called to diagnose roof leaks on an almost daily basis.  These leaks have a common characteristic – they show up when it’s cold.  That usually signals that there is some form of accumulation of water on the roof, usually behind an ice dam, and that the waterproofing is insufficient to stop the water from forcing its way it.  The existence of an ice-dam almost always means that there is excessive transfer of heat to the roof which melts the snow on the upper sections, and the resulting meltwater refreezes on the lower section over the soffits.  To reduce this heat transfer, we rely on insulation (to reduce the amount of heat leaking into the attic) and ventilation (to dissipate the residual heat before it melts the snow on the roof).  However, there is another player in this game, and it can cancel out the efforts at insulating and ventilating.  That player is air leakage.

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Getting three quotes is not enough…

When you look up various web sites advocating consumer help or protection, you often get the advice to ask for three quotes.  The idea is that by getting these quotes, you are protecting yourself from contractors that are going to overcharge you, or from contractors who are undercharging because they are unqualified.  This is excellent advice, but it usually doesn’t go far enough.  As always, the really important stuff is in the details (the fine print).  Let’s examine the issues.

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Frost in Attic

Frost can be beautiful.  One of the benefits of poorly insulated windows, at least for small children, is the beautiful lace shapes that form – so delicate and yet so enchanting.

Despite this beauty, there are plenty of places where in a home you do NOT want to see frost forming.  Certainly, when found on windows, it is a clear sign that the window is not very good at insulating.  Another place where you don’t want to see frost, is inside your attic.

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