This weekend we were able to launch the New Drone at a Townhouse complex in Coquitlam, BC.
This roof would be impossible to inspect using conventional methods such as ladders or binoculars, due to the slope of the property and height of the roof. However – using aerial photography we can see not only the roof, but inspect small details using high-resolution photography:
Flying the Drone at the height of the ridge line, we snapped a few detailed photos in the evening light. In the following photo we can see a broken grill on the flashing (circled).
The strata will be getting a roofer to repair this and the clients were thrilled to see part of the building that would normally be unknown!
When it comes time to replace a roof, homeowners will likely be looking at several different products, and different roofing companies to perform the work. Often, a roofing contractor gives a quote which is much lower than anyone else. This is often a red flag; they may install an inferior material, surprise you with a sudden jump in charges, or simply do the work wrong. One way I see this happen is “cutting back on costs” by not removing the existing roof first – they install the new roof over the old one.
In my career, I have never seen a satisfactory roof that has been installed over an existing one. There are a number of reasons for this…
Double-layer roofs will look good and perform well at first, but often for only a short amount of time. The photo above is from a roof that was only ten years old – far too young to fail this badly. This roof should have lasted 15-20 years.
Due to the poor ventilation of the underside of the new shingles, the shingles overheat in warm weather and deteriorate. This also creates problems with the attic structure/sheathing, which may become damaged.
Certain manufacturers prohibit double-layer installations, and will dishonor the warranty if a roof is incorrectly installed.
And finally, the most important reason not to double-layer a roof:
When the new roof inevitably fails, the roofers will need to remove twice as much material, meaning double the labour and double the disposal cost.
I strongly recommend against double-layer roofing – if you have a property that you think may have a problem roof, a professional home inspection is your best protection against unwanted surprises.
This home in East Vancouver was built in 1979. The roof was original, and was ready to be replaced.
The roof exhibited some signs of failure such as blueberry blisters, ridging, and blistering. The video explains some of these issues as well as giving a good look at some failed chimney and roof flashings.
The buyer negotiated thousands of dollars off the purchase price!
I’ve written before about how getting a new construction home inspected is a great idea. Here’s another great reason why…
We inspected this property in Vancouver, on a sunny day with great visibility. It featured a concrete tile roof, which looked as though it had good ventilation. There were five roof vents that were all flashed nicely. (Not visible in the photo below)
Upon entering the attic, it was clear that there was a problem; in the photo below, we should be seeing the bottom of a vent, not concrete.
TIP: Turn off your flashlight in the attic. Do you see daylight? You should, but only at the eaves (soffits) at the lower edge of the roof, and the roof vents. If you see daylight anywhere else, it may be a leak waiting to happen.
The underlay had been cut, but from below, only the bottom of the concrete tiles were visible. No roof vents.
After going outside to measure, then back into the attic, it became clear that the original installers had misaligned every roof vent. This attic had no ventilation!
Even more surprising? The house was built in 1998. It had been that way for fifteen years!
UPDATE: I returned to this property a few days ago, and the seller had called a roofer to install new metal roof vents. And this time, they were properly lined up! The buyer who hired us ended up saving about $2000.
UPDATE AGAIN: Some neighbours nearby spoke with the sellers, and noticed that their attic vents were also missing. They are currently working on repairs.
This week’s featured inspection is a detached home in the Bolivar Heights area of Surrey, BC.
The house featured a low-slope roof with a torch-on, Modified Bitumen covering.
Walking around the roof, it was clear right away there was a problem with the attic structure. The roof decking was very soft, and sank significantly when walked on.
This is often the first clue that there might be a ventilation problem, or water seepage from the roof above. Another good reason we walk every roof possible, as long as material and safety conditions allow.
Plugged gutters are a common issue with properties with a lot of tree cover. In the above photo we can see that the owner has installed leaf guards at the downspouts – a best practice. However, the gutters still need cleaning as the debris has created a possible overflow.
Some roofing and flashing details were poor. In the below photo we can see that the membrane was loose around the chimney. The chimney had been leaking into the attic for some time.
The attic was in terrible condition – in the next photo we see the plywood sheathing actually sagging. Moisture levels were extreme in this attic – several probed areas showed moisture content as the highest I’ve ever come across. Most of the plywood was deteriorated beyond repair, and active leakage (dripping) was occurring through most of the attic. Mold growth was found in multiple areas.
At this point, one of the only solutions is to replace the damaged portions of the roof structure. Our client ended up negotiating over $10,000 off the purchase price – which will pay for a brand-new roof!
We were called to inspect this property in the Shaughnessy neighbourhood, in Vancouver. The house was an old character home, and upon arriving, a strong, musty smell was noticed at the main floor.
We climbed up to the roof to take a look at its condition:
Here we can see the older cedar roof, with extensive moss growth and deterioration. This roof covering needed to be completely replaced in most areas. Thermal imaging from below showed moisture leakage into the ceiling space, and around the base of the chimney:
When we reached the other side of the home, a moisture stain was visible at the top of the wall:
We climbed up to view the flat roof above – here we can see the built-up (tar and gravel) roof, which was in poor shape. If you look at the wall, you can see the repaired patch where leakage was occurring. The homeowner had “repaired” the leak using roofing tar – an improper and temporary fix. We can also see large amounts of growth on the roof covering.
This inspection included an Indoor Air Quality test, so we sealed off the house and took four air samples, and one air sample outdoors (approximately 9m upwind) as a control sample. The results came back showing high levels of Aspergillus and Stachybotrys, which are both toxic molds (they release mycotoxins, which are harmful to humans). Side effects of these mold toxins include respiratory problems, headaches, fever, and irritation of the eyes, nose, and throat.
Truss uplift is a phenomenon that occurs in a home with a truss roof system (see above picture). In cold weather the bottom chord of the truss stays warmer and drier than the other the members, because it is closer to the heated area below. The other members expand at a different rate than the bottom chord, so it bows upwards, pulling the ceiling up with it.
It looks like this from inside:
Yikes – someone seeing that for the first time might assume that it is a serious structural problem! Don’t worry, though; there are ways to correct it without major expense.
There are a few solutions for this problem:
1. Adequate Attic Ventilation: By preventing a build-up of moisture in the attic, you effectively control expansion of the wood framing members, and lessen their movement during cold/hot weather.
2. Install Sliding Clips: These brackets allow the truss to move up and down without pulling anything along with it.
3: During Construction: Some builders are securing the ceiling drywall to the top of the walls, and not attaching to trusses for a distance of 18 inches from any wall.
4. Install crown moldings, but fasten them to the ceiling only, not the wall. Then when the ceiling moves the molding travels up and down with it, hiding the movement! This is also a good excuse to impress visitors with your interior design skills.
Does your home inspector know what to look for when he sees a crack in the ceiling?
About the Author: David Fairbairn is a licensed, insured, Certified Home Inspector in the province of BC. and holds a certificate in home inspection from Ashton College in Vancouver.
He is also a licensed Power Engineer in BC, and holds a certificate in power engineering from the McPhail school of Energy at SAIT in Alberta. He has been involved in the construction, maintenance and repair of luxury and high-end commercial buildings in downtown Vancouver for many years.
He has a common-sense approach to building science and an innate ability to explain complicated concepts in clear terms.
Call now to book your home inspection! 604 395-2795
All homes need to have their roofs replaced from time to time. There are major differences in materials and installation that will dramatically affect the price and longevity of them. Today we would like to focus on the most common material in our area, asphalt shingles.
When selecting a roof with 3/12 pitch or greater, asphalt shingles are economical;
These shingles will perform well for many years when properly installed by a licensed contractor who specializes in asphalt shingle roofs.
In order to get the best price and value from a roof, we have some tips you should consider, when reviewing a contractors quotation.
1) Does the bid include tearing off the old roof, or is it a roof over?
2) What kind of shingle are they using, is it a Laminated Shingle (also called Architectural Shingles) – 30 years or more, or standard 3-tab shingles (cheaper 15+ year material)?
3) Are there any sheathing repairs in the bid? What material?
4) Bids should include all new flashing, (chimney to roof, siding to roof, skylights, plumbing and vents stacks)
5) Ensure that your contractor will bring your roof up to current standards for ventilation. (1sf of vent for every 150sf of roofing) We see many homes with inadequate roof venting.
6) Assure all bath and kitchen vents are properly vented with dedicated vents for each fan and do not point vent hoses to attic vents.
7) Including zinc strips will dramatically reduce moss problems on your new roof.
Occasionally, home owners will try to save money by ‘roofing over’ an existing roof. This is not usually recommended. A roof that is installed over an old roof will not lay flat, beside other issues. Why would anyone cover up old, deteriorated, damaged, roof covering material after spending all that time and money? Worse yet, what are the current conditions of the underlayment and plywood sheathing that has been covered up?
This can cause the new roof to not perform as well, leading to premature leaks and failure. It also traps more heat, causing the tar in the roof to evaporate petroleum, leading to cracks and failure. In addition, the added weight of another layer can cause structural problems.
As the surest way of knowing, the safest thing to do is to have the roof stripped so that it can be examined for potential structural problems and what the conditions are before resurfacing it and to be sure that you are acquiring a professional roofer that knows what he is doing.
When your roof is replaced, we recommend you choose a 30-year, architectural shingle. Standard 3-tab has a much shorter life, (closer to 15 years). Since the cost of a roof is mostly labour, there is no reason to go for the cheap materials. The labour is the same, and the materials cost about 1/3 more. With double the lifespan, it is the best value for your money.
When getting prices, ask the roofing companies if their bids include any sheeting repairs. Most tear-offs will require some repairs to sheeting. There are two kinds of common products, OSB and plywood. OSB is the standard sheeting used today, but plywood is a more expensive and superior product.
Ventilation is key to a long a lasting roof. When ventilation is poor, it is much more likely to have problems with structural pests in the roof framing and mold in the attic.
A cheap roofing bid will often not include proper venting of bath and kitchen fans.
When these are not properly vented outside, the moisture from them will contribute to structural pest issues and cause the roof sheeting to rot prematurely. Zinc strips will help keep moss from taking over your new roof. This will cost more upfront, but moss will destroy roofs quickly in wet climates.