It is about this time every year that my blood starts to boil, not because it is so hot (like that is going to happen this year), but because I see the vast deluge of contractors out offering pressure washing services to unsuspecting home owners who want a better 'looking' home.
In the last week alone, just in my neighborhood, I have seen two contractors pressure washing roofs (one shake and one asphalt shingle). If you talk to any knowledgeable building envelope professional, they will cringe when you discuss this subject because this cleaning method often leaves behind a trail of destruction long after the contractor has left.
Lets look at each of these in detail. Bare in mind that most pressure washer contractors are like Tim Taylor from the popular TV show Home Improvement, it always makes sense to buy the biggest & baddest monster machine you can get your hands on. Translation - Lots of Pressure!
First the wood shake roof. Wood shakes are usually split. This results in the wood pieces separating from each other along the cell wall boundaries. The wood cell walls are much harder than the cell interior so this process leaves each shake with a hardened surface. This surface provides better water shedding capabilities and stands up better to UV degradation. Most pressure washers have more than enough pressure to strip away the cell wall leaving the softer cell interior. This cell interior absorbs water much easier and breaks down quicker under the sun's rays. The process also saturates the shake (often on both sides of the shake). The shake would not get this wet under normal rain conditions. As this work is normally done in sunny seasons, the top exposed side of the shake often dries quite quickly in the sun and wind, usually much faster than the bottom-hidden side of the shake. This results in stresses to the shake which often lead to cupping and eventually cracking. Now you need to call a roofer to flash all of these new cracks so that you have a properly lapped system again (do not have a cracked shake lining up over a shake seam in the row below). Now you also have a shake surface that is not as durable as the surface that was blasted off with the pressure washer.
The wood shingles fair even worse. These are almost always cut (not split) so the soft cell interiors are already exposed. It takes very little pressure to etch the wood material away. I have often seen roofs during inspections that have up to 1/4" blasted from their surface. They are also much more susceptible to cupping and cracking after a pressure washing incident.
There is also a secondary source of damage created by these contractors. Most wear some form of cleats while on the roof. Think of these cleats as two meat tenderizers on the bottom of their feet as they are producing the exact same effect. In both wood shingle and shakes, the contractor is peppering the surface full of holes that now lets the rain water penetrate to a much deeper depth which in turn accelerates the rate of deterioration of the roof.
On asphalt roofs, the damage created by pressure washers is obvious. A big pile of granules in the gutters at the bottom of the roof. Granules that are needed to protect the waterproofing asphalt substrate from being damaged by the Sun's UV rays. By removing these granules (and even a low pressure pressure-washer will), you are accelerating the deterioration of the roofing system.
Many of these contractors advise their unsuspecting clients that there services will extend the roof and some even offer a 'guarantee' (good luck trying to collect on it). In all of my experiences, the act of pressure washing a roof has significantly diminished the lifespan of the roof not extended it. I consider these contractors as incompetent at best and fraud artists at worst. It is time for the public to demand better. One step would be to require any contractor, who works on any part of your roof system, to be trained and certified by the Roofing Contractors Association of BC. That way, they would be required to follow the RCABC best practices guide even when it comes to maintaining a roof's surface. Homeowners can check out the RCABC Consumer Guide for instructions on how to properly maintain a cedar roof (pg 117).
Do not be duped by these contractors. Do your research and get informed. Say no thanks to any contractor who offers to pressure wash any part of your homes exterior.
Thursday, June 23, 2011
Thursday, May 5, 2011
Home Inspections
Have you had an excellent or horrible home inspection? Lets us know.
We want to know what YOU think makes a good home inspection and what it is you hope to achieve by hiring a home inspector.
Comment on this post or send us an email at inspector@bchouseinspections.ca
We want to know what YOU think makes a good home inspection and what it is you hope to achieve by hiring a home inspector.
Comment on this post or send us an email at inspector@bchouseinspections.ca
Monday, March 14, 2011
Home Inspections and Infrared Cameras
Ever since Mike Holmes broadcast his first 'Holmes Inspection' program, home inspectors across Canada have been clambering to buy the cheapest Infrared (IR) Cameras and offer 'IR services' as part of their inspection process.
Now any press for the home inspection industry is generally a good thing, but I am afraid the Mike Holmes inspection show has done more harm than good, in that it portrays the services of an inspector in an unrealistic way (but more on that on a later post - back to the topic).
A home inspection is best performed by an individual with a broad base of knowledge of all the systems and components in a home. The inspection is visual in nature, as we as inspectors are not authorized to perform destructive testing/investigation. The addition of an IR Camera would seem like a godsend for an inspector, as it would allow them to 'see' behind walls.
However, as with most things, it is not that easy. The cameras that most inspectors are buying are at the bottom end of the technology and cheap (<$5K). They are very low resolution and a very narrow scope of field with limited accuracy. Even a professional would be hard pressed to use these cameras in anything but the most basic and focused of investigations. The concept that a home inspector can use these to 'scope the house' is ludicrous. The technology does represent an excellent opportunity for a home owner or purchaser to asses a dwelling from the standpoint of thermal bridges (missing or poorly detailed insulation), air leakage (poorly detailed air barrier), and even moisture issues (rain leaks, plumbing leaks, & condensation in the walls). However a meaningful and accurate result can only be accomplished by using professional equipment (Still priced in the $10K range) and utilizing an inspector who has the required training to operate the camera, understands the building science that indicates where and how to look, and has the overall experience and field training to interpret what the camera is 'seeing'. For single family homes this means having at the very least, a Level 1 ASNT certification. If the inspector is providing IR inspection on Multi-Family or Commercial properties, they are then required to have a minimum Level 2 ASNT certification. This represents an additional $2-5K in training on top of the camera cost. And in order to stay current on their skills, an IR inspector has to use the technology at least weekly (preferably daily) and must continually update their education and equipment over time. In fact the certification program requires the inspectors to continually update their training as part of the certification program, which is why you want to ensure your IR inspector has a current certification certificate.
A typical non-trained home inspector would look at this photo and state that the upper windows are cooler than the bottom windows, when in fact the upper windows are reflecting the night sky radiation off the Low-E coatings on the window, due to the viewing angle of the camera and are most likely hotter than the bottom windows, due to the stack effect that would be present in the tower.
The facts are, that in order to perform quality Infrared inspections you must have the right equipment and right training behind you, and then you must perform the inspection under controlled conditions at the right time of the day. Criteria very few home inspectors have met, have knowledge of, or can even afford if they do.
The 'IR' services that many home inspectors are advertising are really more of a marketing gimmick, as opposed to providing the client any real level of additional security against liability. The services usually represent negligence at best (providing a service they are not trained to perform) and sometimes even fraud at the worst.
At this point SENWI will not be providing Infrared Services and will instead leave it to the experts. We will instead provide the best visual inspection we are capable of providing and when warranted, recommend an independent IR inspection follow up by a contractor who performs IR inspections as their major business activity, and who has a current Level 1 or Level 2 certification.
One source of professionally trained thermographers is City Green Solutions
Should you wish to discuss the issues of IR inspections with us further, please feel free to contact us at mailto:inspector@bchouseinspections.ca?subject=IR%20Inspections
So, do not fall victim to those that claim to provide 'IR Inspection' as part of their home inspection services, but do not have the equipment or training to provide this service competently. Look for these warning signs that the inspector does not have the proper training to perform an IR Inspection:
Now any press for the home inspection industry is generally a good thing, but I am afraid the Mike Holmes inspection show has done more harm than good, in that it portrays the services of an inspector in an unrealistic way (but more on that on a later post - back to the topic).
A home inspection is best performed by an individual with a broad base of knowledge of all the systems and components in a home. The inspection is visual in nature, as we as inspectors are not authorized to perform destructive testing/investigation. The addition of an IR Camera would seem like a godsend for an inspector, as it would allow them to 'see' behind walls.
However, as with most things, it is not that easy. The cameras that most inspectors are buying are at the bottom end of the technology and cheap (<$5K). They are very low resolution and a very narrow scope of field with limited accuracy. Even a professional would be hard pressed to use these cameras in anything but the most basic and focused of investigations. The concept that a home inspector can use these to 'scope the house' is ludicrous. The technology does represent an excellent opportunity for a home owner or purchaser to asses a dwelling from the standpoint of thermal bridges (missing or poorly detailed insulation), air leakage (poorly detailed air barrier), and even moisture issues (rain leaks, plumbing leaks, & condensation in the walls). However a meaningful and accurate result can only be accomplished by using professional equipment (Still priced in the $10K range) and utilizing an inspector who has the required training to operate the camera, understands the building science that indicates where and how to look, and has the overall experience and field training to interpret what the camera is 'seeing'. For single family homes this means having at the very least, a Level 1 ASNT certification. If the inspector is providing IR inspection on Multi-Family or Commercial properties, they are then required to have a minimum Level 2 ASNT certification. This represents an additional $2-5K in training on top of the camera cost. And in order to stay current on their skills, an IR inspector has to use the technology at least weekly (preferably daily) and must continually update their education and equipment over time. In fact the certification program requires the inspectors to continually update their training as part of the certification program, which is why you want to ensure your IR inspector has a current certification certificate.
A typical non-trained home inspector would look at this photo and state that the upper windows are cooler than the bottom windows, when in fact the upper windows are reflecting the night sky radiation off the Low-E coatings on the window, due to the viewing angle of the camera and are most likely hotter than the bottom windows, due to the stack effect that would be present in the tower.
The facts are, that in order to perform quality Infrared inspections you must have the right equipment and right training behind you, and then you must perform the inspection under controlled conditions at the right time of the day. Criteria very few home inspectors have met, have knowledge of, or can even afford if they do.
The 'IR' services that many home inspectors are advertising are really more of a marketing gimmick, as opposed to providing the client any real level of additional security against liability. The services usually represent negligence at best (providing a service they are not trained to perform) and sometimes even fraud at the worst.
At this point SENWI will not be providing Infrared Services and will instead leave it to the experts. We will instead provide the best visual inspection we are capable of providing and when warranted, recommend an independent IR inspection follow up by a contractor who performs IR inspections as their major business activity, and who has a current Level 1 or Level 2 certification.
One source of professionally trained thermographers is City Green Solutions
Should you wish to discuss the issues of IR inspections with us further, please feel free to contact us at mailto:inspector@bchouseinspections.ca?subject=IR%20Inspections
So, do not fall victim to those that claim to provide 'IR Inspection' as part of their home inspection services, but do not have the equipment or training to provide this service competently. Look for these warning signs that the inspector does not have the proper training to perform an IR Inspection:
- They advise that they will be providing IR services during a brief 4 hour or less home inspection.
- They advise that they will be performing the IR portion of the inspection during daylight hours (After sunrise or before sunset is required for accurate readings).
- They advise that it will be easy to identify water related issues on the interior or exterior of the home. (nothing could be further from the truth)
- They advise they will only do an interior or exterior scan of the home (not both as is required for accurate interpretation).
- Ron Newport, Director of Institute of Infrared Thermography agrees with these sentiments and indicates a complete and thorough IR inspection of a standard single family residential dwelling will take in the order of 4-6 hours (this is just for the IR portion, the inspection has not performed any regular home inspection tasks yet). The City Green website indicates that their thermal imaging assessment overview takes on average - 2 hours.
- Most thermographers will take any scans of the exterior of the home prior to sun-up or after sunset. The whole purpose of using an IR camera is to look for temperature differences (indicated by the infrared light that radiates from an object) between various building components and trying to determine if they make sense. Once the sun is out, much of the 'evidence' is wiped out as the surfaces heat up under the sun's rays. This will also very quickly effect the readings on the inside face of exterior walls and so even interior scans are often done before the sun has reached the particular wall(s) of concern.
- Even a seasoned IR inspector, with the best equipment, will advise that finding moisture issues is one of the hardest tasks to perform with an IR camera. In order to perform this task, the technician usually has to artificially cause a significant temperature change to the structure of concern (often also accompanied by artificially lowering the air's humidity in the region). This investigation takes a very thorough knowledge of building science (something the vast majority of home inspectors due not have) and preparation, and even then can often not be conclusive.
- In order to get a true 'picture' of the situation, a good thermographer will scan both the interior and exterior of a dwelling to allow a comparison between the two surfaces and allow the development of a hypothesis of what is happening within the building structure at that location. Just think, would a home inspector ever inspect just the exterior or interior of a home and advise that a given building envelope was OK based on only seeing only half of it?
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