Water is the Enemy; A Home Inspector’s View

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One of the many things a home inspector looks for is evidence of the entry of water into the building envelop. That’s just a fancy way of saying that water has gotten inside and its left a stain or other damage. So is seeing a stain a big deal? Maybe not, but we should always treat it as if it is until we know for sure. The real question is has the problem been fixed and what damage has the water done in the mean time? This can be impossible to fully assess from just a visual inspection and in severe cases contractors may have to be called in to open up the walls. Left for prolonged periods, even modest amounts of water can do a lot of damage to a home. In this article, we will provide an overview of a number of ways that water can enter or be trapped inside a modern home.

Interior water leaks are bad enough when they do cosmetic damage warping hardwood floors, softening drywall and bubbling paint. The repairs can be many thousands of dollars and a severe inconvenience to family routine. Things get more serious when structural damage is done. The presence of water is one of the main growth factors required for mold as explained in Household Mold De-Mystified. Of course another name for mold is ‘rot’ and having the lumber holding up your home rot is a serious issue indeed. Not only is the strength of the building compromised, but the framing is often covered with layers of ruined building materials that must be removed and replaced. The bills can add up quickly.

Let’s start with the roof and work our way down. Although most people naturally suspect the shingles to be the prime culprit, if they are properly installed, it’s much more likely to be the flashings that are at fault. Flashings are metal or rubber trim pieces used to seal a roof in valleys, along surface transitions and around openings like skylights and plumbing stacks. The flashings are intended to sheet water safely over a joint between materials. Unintended openings can start in ageing caulking and from the expansion and contraction of joints. Properly applied, a five dollar tube of caulking can save you thousands of dollars of repairs.

Somewhat similar problems can be discovered as we inspect the building exterior. Door and window openings need well maintained caulking as well. Poorly installed siding can capture water rather than shed it away. Brick or masonry walls that are cracked and let moisture in can be expensive repairs in their own right. Sometimes we see masonry walls that have been built without weep-holes or that have had them plugged up by a well-intended home-owner. The weep-holes are there to allow water otherwise trapped behind the wall to drain out. Blocking the holes defeats the purpose of the weep-holes and can cause significant damage to the wall and house framing behind it.

At ground level, we look to see that precipitation is able to readily drain away from the foundation. I don’t think most people appreciate the importance of handing all the water that can fall or run onto a property. Even a moderate rain can deliver thousands of gallons that all flows downhill. We want to keep that water from flowing into your basement. The remedy starts with the eves-trough. They capture all that water that falls on the roof and discharges through the downspouts in am attempt to get it away from the house’s foundation. In nearly every house that we visit, we find that the downspouts drain too close to the foundation wall. We routinely recommend the installation of downspout extensions to take the water far enough away to protect your basement. We recommend a six feet as a normal objective and to make sure that it end on ground that slopes away from the building. See Tips to Help your House Make the Grade

City building departments all ask for grading plans for new houses these days. They know that all that storm water needs to be properly dealt with. This applies to all houses, but especially if your house is built at the bottom of a slope or below the level of your neighbours, you need to be careful that grading around your foundation runs water away. Its very common to find settling of the fill around the foundation wall has created a depression that feeds water right to the wall. Your driveways, patios and sidewalks should also be modestly sloped away from the house for the same reason. Even-though builders often wait months to pave driveways, the majority of subdivision homes have significant settling in front of the garage door. Besides being a trip hazard, water ponds and freezes creating slip and fall opportunities for home-owners and unsuspecting guests.

We’ve worked our way down to the foundation walls. If the property is doing a good job of draining water away from the house, we are much less likely to find a damp or out-right wet basement. That being said, there can be groundwater to deal with as well. Modern poured concrete foundations are damp-proofed with tar and a dimpled plastic membrane that channels water to the foundation drainage tiles. Sump pumps or natural drainage is used to to handle any water that might otherwise accumulate underneath the slab. Properly functioning these measures eliminate water outside the wall that might try to find it’s way in.

Now we need to consider the potential internal sources of water in a home. People underestimate the amount of water that is in the air of a modern home. Indoor plumbing has brought water problems indoors too. In the old days, homes weren’t sealed so well and if things got damp the air leakage helped dry things out fairly quickly. Nowadays the water that enters a home stays there unless we take steps to remove it. Excess humidity can come from many sources: steaming cooking pots under an unused range hood, long showers without bathroom fans on, and blocked clothes dryer vents are just a few examples. Once that moisture is in the air it travels to a cold surface and condenses depositing water on surfaces that may rot or produce mold. Some times one water problem leads to another. A toilet that runs continuously can waste a lot of water, but it also chills the toilet tank and supply piping which can create puddles in the wrong places. If the humidity levels get high enough, mold can show up anywhere there is an appropriate foodstuff.

We’ve covered a lot of ground, but these are only some of the ways water can enter a modern home. Fortunately many techniques and technologies have developed to protect us from water entering our homes and others to help us to remove it when it does gets in. We have heating, air conditioning, heat recovery and other ventilation systems that attempt to manage our comfort, air quality and humidity in our homes. This all adds to the complexity of our homes. I’ve tried to give an overview of the many vulnerabilities to water that our homes have. You can follow the links provided to other articles which address specific concerns in more depth. The most important message I can offer you is that if you notice a water problem starting to occur, the faster and more professionally you deal with it, the less trouble and expense you will have to go through over the long run.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Household Mold De-Mystified

Mold are asexual fungi. They reproduce via spores which are small enough to be easily carried in air currents. As a consequence, mold is virtually everywhere. It’s not a question of whether there’s mold in a any given house; it’s a question of how much. As a home inspector, I know my clients are concerned about the levels of mold in the house they are considering buying, but determining the quantity, variety and measures to be taken for remediation are beyond our standard of practice. In fact, we even resist using the term ‘mold’ before the buyer has test results in hand. We will however raise questions should it become apparent that further investigation is warranted. Specialists can come in to take samples for examination at a lab.

Attic hatch seal Basement wall
Air leak at attic hatch Damp floor wicks up wall
Discoloured roof sheathing Toilet condensation
Poor ventilation in attic space Condensation from toilet
Wet bedroom wall Wet subfloor around toilet
Wet bedroom wall Wet subfloor around toilet

Buyers and agents often focus on the suspected mold as the problem. They worry about the health risks of exposure and allergic reactions. Legitimate concerns, but they need to understand that mold is actually a symptom of other underlying problems. For mold colonies to grow they need four things: a few spores to seed the colony, organic material to feed upon, moisture at suitable temperature and time to sporulate or reproduce. Our homes are full of organic materials like, wood framing and trim, paper coatings on drywall, exfoliated skin cells and soap scum in bathroom fixtures. We can’t eliminate these materials, nor change the temperature range we maintain in our housing. The factors we must control are the presence of moisture and how long it remains. Without fail mold colonies are found in moist environments.

Home inspectors are trained to look for signs of discoloured building materials in damp areas. Attic spaces are susceptible due to high humidity levels if ventilation is poor or through other poor building practices such as terminating plumbing stacks or ventilation ducts inside the space. It happens more that you would think. That moisture produces black patches that can cover the entire underside of the sheathing. Long, hot showers without turning on the bathroom fan can trap a lot of moisture in a home. Condensation from toilet tanks and leaking seals can be a source of moisture that rots wooden floor sheathing. Blocked clothes-dryer vents are a common source of humidity. Basements are particularly susceptible for a number of reasons, not the least of which, is that water will run to the lowest level it can. Less obvious sources are back-drafting furnaces and gas water heaters that can produce large amounts of humidity, not to mention deadly levels of carbon-monoxide. Unfortunately we can’t tear things apart to look for problems inside walls so there’s a limit to how much can be detected visually.

Modern homes are designed to remove as much excess moisture from a home as possible. Improved attic-space and bathroom ventilation, damp-proofed foundations, weeping tiles, floor drains, sump pumps and heat recovery ventilators are all innovations designed to control interior moisture levels. Humidity can vary greatly but as long as high levels are brought under control relatively quickly (under 48 hours), mold doesn’t have the time to sporulate and its growth is curtailed. So the best strategy is keeping things dry and if a mishap occurs make sure it gets taken care of in short order.

Mold is a surface phenomenon. Test kits are available if you want a lab to pin down specifically what you are dealing with. But in general if it smells funky, it’s there somewhere. If you recognize a small problem area early enough you can clean it up yourself with soapy water or by wiping with alcohol. This won’t address any staining but it will kill the fungi. Dead spores are just as toxic as live mold so get rid of any rags or sponges used in the cleanup. Anything very extensive will require professional removal or remediation, but this can be a significant cost. So get a handle on any problems early on and remember that any repairs you make to keep your home dry are helping to avoid major expense and potential health issues later.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Infrared Home Inspections; More Guesswork than Detection

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The short and simple explanation of an infrared camera is that it displays a picture that represents the various temperature readings of the surface it is focused on. The camera can’t see behind the surface. As a home inspector, you have to apply your knowledge and experience to ‘interpret’ the image. You could just as easily describe it as an educated guess. Well hopefully education is part of the analysis.

I am still skeptical about the use of infrared cameras during a home inspection. I could be convinced with a compelling argument and evidence of course, but in the mean time I question whether the use of infrared cameras should be part of a standard residential home inspection. While this ‘sexy’ new tool searches for markets to exploit, you might want to rethink how much value it brings to the table in a home inspection.

I’m sure there are enthusiastic proponents out there who sell the cameras and the required training needed to ‘interpret’ the ‘results’. The many inspectors who have invested the time and money to offer ‘infrared inspections’ have a stake in the game as well and may be emotionally and financially committed to the device.

All home inspectors are aware of infrared cameras but many choose not to use them. Even inspectors who have purchased them often seem to lose their enthusiasm for using them on home inspections. Price is less of a stumbling block than it was, as it has fallen considerably, but still infrared cameras have not swept the marketplace. They are just not necessary to do good home inspections. In fact, I think they take up time that can be better spent inspecting the property visually. The industry claims that with just a ‘few minutes per room’ you can add infrared inspection to your routine. Conservatively that adds over an hour to an inspection, or takes time away from current investigation activities.

I have attended about thirty home inspections with a trained infrared camera operator. Only once did he suggest to a buyer that he saw something of interest. It turned out to be a minor and totally meaningless observation that added no value to the inspection. One of his practices was to use the camera to confirm temperature of airflows from heat registers throughout the house. I can pretty much rely on my hand for the same purpose. In questioning the inspector, I can’t remember any great stories he had to offer of catches that otherwise would have gone undetected in the previous couple of years of infrared use. His own observation was that the camera was ‘mostly a marketing tool’; meaning that it looked cool and people might prefer to have their inspector use one but they wouldn’t pay extra for it. If infrared cameras were really that beneficial in home inspections surely by now the marketplace would be demanding their use and people would be lined up to pay an extra fee. The reality is nothing like this.

There is only so much time that can be spent on-site a a home inspection. There are lots of things to inspect and many signs to look for that help experienced inspectors to detect defects without the use of an infrared camera. I am not saying that once a problem is detected that infrared cameras might not help in assessing the extent and confirming the specific location of a problem. But I would suggest that it is more than just a coincidence that the inspectors who throw in a free infrared camera inspection tend to be the lowest price practitioners in the market as well. Before you fall for lure of the sexy technology on your next inspection, I would give more thought to what the inspector brings to the table in terms of know-how and genuine caring than his tool-bag.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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When Should I Change My Furnace Filter?

Conventional furnace filters capture dirt as it returns from the house before it enters the blower compartment. This means that the side furthest away from the blower, or fan, is the one that’s going to get dirty. As time goes on, the dust and dirt clogs in the pores of the filter and then starts to accumulate in a layer on the filter. If you can easily tell the difference in colour from one side to the other, the filter is ready to be changed. The change is overdue if it looks like there is a dirty blanket of lint built up on the filter.

Filter change past due. Collapsed furnace filter.
Way past due. Sucked into the blower.

So why do some people say to change it every month, while others say three months and some say as long as a year? All these answers are correct for someone, but might not be right for you. The time frame that it takes for a filter to get dirty enough to replace varies by a number of factors. Families with pets, or that have a woodworker creating sawdust in the house are providing more particulate matter for the filter to catch. Some people buy filters that have very fine pores in them to capture pollen and such to help a family member with allergies. These smaller pores clog up faster. In each of these cases, furnace filters are going to need to be changed more frequently.

Conventional filters are one inch thick. Some high end filters have a special housing that hold filters that are as much as five inches thick. Because the pleated filter medium they use has so much surface area, they typically last much longer.

A clogged filter lets less and less air through to the furnace. The blower motor has to strain to provide air to the furnace and may eventually fail; requiring an expensive repair. In other cases, the fan can pull the clogged filter right into the fan compartment. With the filter collapsed and out of the way, dirt will get straight through to the furnace components that the filter was designed to protect.

As a home inspector, I often find filters that are past due for replacement. It seems like a minor oversight but the cost can be significant. You should check your filter every month until you get used to the frequency that suits your family. Set a repeating alert in your smart phone to remind you when you need to have a look.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Beyond Staging: A Better Home Inspection Report

Conventional sales advice calls for removing the clutter from a home when you put it on the market. Tiding up a home’s appearance helps prospective buyers to picture themselves living in the home without the distractions of the previous owner’s personal belongings. More recently, this has evolved to include staging the home with rented furniture and sometimes a certain amount of judicious redecorating. With the right professional help, staging can make a tremendous difference in the appearance and marketability of the house. This is all the more important in a buyer’s market where you need to differentiate yourself from other properties in the same price range.

You’ve done all the right things to beautify the house on the surface. Why not take a little more time to remove the easily addressed defects beneath the surface? They may not be obvious to the seller or the prospective buyer, but to a Home Inspector they are. By the time the inspector arrives, you have a deal on the table and it seems as if he or she is pouncing on tiny little flaws in an otherwise beautiful home. Each defect, tiny or not, adds to the volume of the report and to some degree can taint the buyer’s overall perception of the house. A short repair list is a lot more attractive to a buyer.

Missing cauking is a quick fixAs a Home Inspector, I see lots of defects that a few minutes attention could fix. It can be as simple as a broken cover-plate on an electrical switch or receptacle, a dirty furnace filter or some missing caulking. Some defects can be addressed with a little physical effort and some might call for a few dollars investment. Here’s a guide that explains a variety of common defects and organizes them starting with the quick and cheap fixes. There’s also a checklist to help manage the work. You don’t have to be a trades-person to do these repairs. But if you are just not into the do it yourself stuff, hiring a handy man for a few hours can get a lot done in a hurry.

By all means acquire the skills of the best Home Stager you can find. They know how to put the right colours and items together to present your home at its best. None the less, a bit of work on your part might cut down the number of defects by as much as a third. Remember, a thinner inspection report is always better report. So if you want to do everything you can to sell your home, take a step beyond staging.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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How to Fall Off a Ladder

Those of you who wish a long, healthy and unexciting life will probably not want to read this article. You’ll be one of those folks who always sets up your ladder on level ground; consistently leans it against a solid surface at a ratio of four units of height to one unit out from the wall; secures the top of the ladder; thinks to use a non-slip map under the ladder’s feet on a wet or slippery surface; and always keeps a hand free to grip the ladder.

Now those of you willing to trade a little excitement now for a lot of discomfort later, you can always flaunt the guidelines above. If you disregard them in creative combinations you’ll never know what heights of adventure you may reach. Do make sure you have a video camera filming every climb because we won’t want to miss it on Youtube. Speaking of which, here is an excellent educational video from a health and safety instructor who missed out on the guidelines.

There are some truly inspired ladder climbers out there. Here are a few pictures that show what’s possible if you take your ladder climbing to extremes. Can you imagine the pictures we missed of the extreme climbers who didn’t have any friends left to film them? Perhaps someone thought to immortalize their efforts with a Darwin Award.

So why would you want to fall off a ladder? Well a couple of ideas come to mind. All you have to do is fall off a ladder once or twice early in a relationship and you are pretty well excused from any maintenance jobs involving a ladder for all time. There is always the invalid/pity gambit to exploit as well. Deliberately crippling yourself can really payoff for about six weeks of meals served on the couch and in bed. Of course there’s the rest of your life to think about.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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A Stairway to Heaven

Properly built and equipped stairs are easy to use whether you are familiar with the house in question or not. Unsafe stairs are an accident waiting to happen. The homeowner may claim that, “those stairs have been like that for years and no-one has gone to the hospital yet”. The keyword is ‘yet’. Along with other criteria, home inspectors want to see stairs that are: solid; level; consistent and compliant in step height and tread depth; have sufficient head-room; are well-lit; and appropriately guarded by handrails and ballasters.

It doesn’t seem like much of a big deal when one step is a different size, but if you expect the next one to be like the last one, the surprise can easily take you for a tumble. We often see this on decks where pre-cut stringers or improperly installed interlock create an odd-sized step at the top or bottom. Stairs must be custom fit to evenly divide the overall height between the platforms with a consistent rise that conforms to the range specified in your local building code. Here are a few examples of the kind of things we often see.

Trip hazard Inconsistent steps
Trip hazard Inconsistent steps
Stair with no light or handrail Stairs not level
No light or handrail Stairs not level
Stair with no landing or handrail Stairs broken
Stair with no landing or handrail Stairs broken

Not having sufficient light in a stairwell is risky. Having no light and no handrail is temping fate. Each additional non-conforming factor just adds to the risk. Broken stairs and treads that aren’t level can be treacherous. Exterior stairs can ice up in cold weather and be very slippery. Landings are required to safely enter and exit buildings with more than three risers.

Home inspectors pay such close attention to steps and stairways to improve stair safety. According to the mortality data from Statistics Canada, there were 388 deaths due to falling down stairs and steps (table 102-0540, 2009). One can only assume that there are many times more stair-related injuries as well. If you recognize any of these issues on the stairs in your home, take corrective action now. Make sure that the only stairway to heaven in your home is on a playlist.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Don’t Get Hosed by your Washing Machine

Traditional rubber washing machine hoses that feed hot and cold water to your washer can deteriorate over time. This makes them susceptible to rupturing and potentially flooding your home. The recent trend of locating laundry facilities on the second floor of the home for proximity to the bedrooms further exacerbates the problem, as the flooding occurs in finished areas of the home rather than a basement. Having a drainage tray installed is a good and helps if the pump housing breaks, but ruptured hoses will spray in all directions circumventing the tray’s protection.

Below on the left is a picture of a washing machine supplied by rubber hoses. On the right you can see what steel-braided washing machine hoses look like. You can buy them in a package of two for about twenty-five dollars at the big box hardware stores. All you need is access to the back of the machine and a pair of pliers to install them. The principle is that the wrapping of the hose with the steel braid reinforces the hose and does a better job preventing ruptures. Make sure there are no kinks after you install your new hoses.

rubber supply hoses steel-braided hoses

While we’re on the topic, you can lessen the risk by turning off the shutoff valves while you are away on vacation. A lot of water can pass through a pressurized hose in a week or two. Newer plumbing installations (as per picture to the right above) have a single lever ball-valve that makes this easy. Of course you still have to remember to use it.

Is age the only factor that causes rubber hoses to burst? Well, probably not. Another factor that I think contributes is water-hammering. The solenoid valve in a washing machine that controls the water flow pretty much goes from full flow to no flow in a split second. The sudden stop of the pressurized water really hammers the pipe and supply hoses. Not all all water supplies have hammering that you’ll hear, but the surge of water still sends a shock wave through the line. Like most things in life, the weakest components fail first. If you have old rubber supply hoses, you have a flood waiting to happen.

Anti-hammering devices can be installed between the hose connection and the supply line to reduce the effects of the hydraulic pressure wave. They act as a shock absorber to reduce hammering and the noise that commonly accompanies it. Here’s an article at About.com that shows you an anti-hammering device and discusses how to install them.

As a Home Inspector I frequently comment on rubber supply hoses to washing machines.I hope these tips help you to be comfortable and safe in your new home.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Factory-Built Modular Homes

Modular homes are an approach to modern construction that has slowly been gaining acceptance. Probably because the efficiencies of constructing buildings in a factory setting has several advantages. Regardless of the weather, the materials and crew are protected indoors; water damage is eliminated and productivity is high. On-site time is greatly reduced and much of the construction waste is handled at the factory.

I recently went on a tour of Guildcrest Homes in Morewood, Ontario, just outside of Ottawa. Several model homes are on display at the property to help purchasers see some of the many designs available, but the real action is in the factory behind. In a one hundred thousand square foot building, house modules start their life at one end of the building and emerge at the other end packaged and ready to ship. The company manages the construction process through eighteen stages of completion supplying materials and related tradespeople as required.

First wall on deckIn the first stage, the deck is built and set onto steel wheels that guide the developing module through the factory on tracks in the floor. Here we can see that a protective layer of paper has been laid down on the deck and the first wall section has been lifted into position by crane. The section already has vapour -barrier and drywall installed. To the right, we can see a module that already has its interior and exterior wall sections in place.

Walls upThe factory has workshops that specialize in producing various sub-components like stairs and roof trusses. The sub-components are made to the custom requirements of the individual module’s design and transported to the factory just in time for assembly. With the framing done and drywall in place, crews can work to install electrical and plumbing from the outside and the interior through openings in the drywall where required.

Siding and trimInsulation, sheathing, windows and doors, siding, soffit and facia trim are all applied on the exterior while drywall is taped sanded and painted on the inside. The completed module will have shingles and interior finishes including flooring, cabinets and plumbing fixtures installed. Sufficient wiring is bundled at the end of each electrical circuit to complete the run to the electrical panel. I’ve glossed over the work performed here pretty quickly because the materials are not unique its the environment and the order they are installed in that differs.

In normal construction emphasis is on getting the building envelope sealed so that materials are protected and the work then shifts to building from the outside shell inwards. In the factory environment, once the drywall is installed work can be performed on both sides of the wall. Supply of materials is much easier, as is working from a level concrete floor or from permanent overhead scaffolding when shingling the roof.

Ready to travelAt the end of the production line, the module is wrapped in plastic to protect it from the wind and elements while shipping. Hydraulic jacks lift the module off the steel wheels and onto higher stands. A transport truck backs a trailer under the module and it is lowered to be hauled away. Guildcrest’s website has a nice sequence of shots showing the craning of the finished modules onto a waiting foundation. Their installation makes for a dramatic advancement in a single day at the construction site. Of course there is still work to be done on site to link the modules together, connect electrical and plumbing runs and install any brick veneer or stonework required.

Guildcrest estimates that only one percent of the new-build housing market is being supplied by factory-built modular homes. Given it’s advantages we are likely to see more of this approach to residential construction. As a home inspector, I like the potential of higher quality construction in homes that are better sealed from the elements. If significant cost savings are passed on to the consumer, expect to see more modular homes going up in a subdivision near you.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Engineered Trusses

The traditional method of assembling the wood framing members that hold up a residential roof structure was a manual process of custom cutting rafters, ceiling joists and the various pieces required. For the last couple of decades, virtually all roof framing is built as factory manufactured components that are assembled on site. There are several advantages to this approach. Engineered designs allow greater loads to be carried with smaller dimension lumber; saving material costs. Greater uniformity in the components helps with the quality of construction. Factory automation provides labour savings on-site as trusses can be lifted into place as finished components. Less skill is required in the field and roof structures can be framed in less time.

Truss manufacturing companies serve builders by efficiently producing trusses at their factories and shipping them to the construction site. Smaller trusses are lifted by hand and larger ones are often lifted by crane to be installed. The process start with specialized design software that takes design parameters as input and creates truss designs that meet load, span and code requirements. In large part, trusses form a repetitious design element where each truss is offset parallel to the next by a standard amount.

A truss is made up of a top and bottom chord and supporting pieces between called webbing that are often arranged in a triangular pattern. There are truss designs to accommodate different requirements like cathedral ceilings, attic storage, tray ceilings and so on. Truss manufacturers cut several of each component and assemble the parts in jigs for speed and accuracy. At the joints, the pieces are held in place by a gusset, which is a plate with many fasteners. In earlier versions the gussets often were a piece of plywood covering the end of several parts held together with numerous nails. Now the most common gussets are galvanized sheet metal cut with many tangs that are pressed into the wood.

Laying out truss components

You can see how the workers assemble each part of the truss on a table according to the design. Gussets are laid on the joints and a press rolls into position and pushes the tangs down into the wood for a strong and secure joint. The process is repeated over and over until enough trusses have been produced for the house. Then they are shipped to the construction site. The first picture shows the layout of pieces and the second the press in action.

Pressing the gussets

In the example shown the trusses are relatively small and only form one half of the roof for a modular home. It’s not uncommon for trusses to span more than thirty feet in length and take the entire load for that distance. This removes the need for load bearing walls in the interior space of the house and facilitates open designs and subsequent interior renovations. Because trusses carry so much of the load in a house, it is critical that the design follows engineered specifications and that the plan is followed accurately on site. Municipal building officials help to ensure that code issues like nailing, bracing and other requirements are consistently applied. As home inspectors, we visually examine the trusses, typically from an attic hatch, to see if we can spot any damage to truss components or improper modifications. Given the limited view possible from this vantage point it can only be a cursory examination.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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