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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Knob and Tube Wiring

Knob and Tube wiring was one of the earliest techniques used to distribute electricity in our homes. It’s referred to as Knob and Tube because of the ceramic insulators that were used to pass the wire through and around obstacles. The Tube lined a hole through a stud or joist and the wire fed through it to protect the structure from contact. Knobs were used to secure the wire and at points with changes in direction. The wire itself was a product of the times; copper with a cloth woven covering impregnated with a waxy substance to protect the wires from moisture. Unlike modern wiring, each conductor was a separate wire and there was no ground wire.

Aluminum wires in electrical panel

The first installations were all retrofits and the wiring was mounted on wall surfaces. As new homes were built knob and tube wiring was incorporated into the wall structure like today’s wiring is. Since using electricity was new, there were very limited uses for it and the amount of current supplied was small, typically 30 amps. Today’s homes use at least 100 amps and in those of any size 200 amps is common. As new electric appliances, televisions, computers and other devices came along electrical services were upgraded in older houses.

It wasn’t overly difficult to upgrade the electrical service and distribution panel, but the existing distribution wiring hidden in the walls was a greater challenge. The effort and disruption of opening walls to replace the wiring was more than many homeowners were prepared to undergo. Often older houses developed into hybrid systems. This left sections of Knob and Tube wiring in some of the more difficult to access original sections of the home and updated wiring was used in remodelled sections and new additions.

This is part of the reality that home buyers face today when purchasing homes that predate about 1940. Somewhere in that building one or many runs of old Knob and Tube wire may still be hidden in the wall. It’s not that the wiring doesn’t work, but it doesn’t meet modern electrical and safety standards. Amateur connections between old and new wiring can be problematic and because the presence of Knob and Tube is considered undesirable, old wiring is sometimes left hidden and goes undisclosed. To be fair, the current owner may have no idea that it’s there.

Ultimately this falls into the risk that a home buyer accepts when they purchase an older home. Along with the charm comes the workmanship and technology of the day. As Home Inspectors, we look for signs of Knob and Tube wiring, but it’s a visual inspection and we can’t open up the walls to satisfy our curiosity. Another reason that Knob and Tube wiring becomes relevant at the time of purchase is that insurance companies are none too fond of it. You may have fewer companies to choose from, and those that do cover it, may do so at a higher cost.

The purpose of this article was to help you understand Knob and Tube wiring and the issues it raises in buying older homes. Wiring issues can be always be addressed with enough effort. It is just one of many issues to be considered and a licenced electrical contractor should be consulted when it is discovered. Hopefully the remaining use of Knob and Tube is limited and the associated costs to upgrade will be manageable.


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

First of all, aluminum is a good conductor. It weighs less and costs less than copper. That’s why utility companies have been using it in their transmission lines for many decades and continue to do so to this day. From the mid-sixties to the late seventies aluminum wire was installed in residential electrical systems because the price of copper had spiked. You may have heard that the presence of aluminum wiring in a house is a cause for concern. I’ll try to explain what the issues are and you can decide what to do from there.

The primary concern is the risk of fire from improper installation. It all happens at the connection points. Aluminum oxidizes when exposed to the air. This really doesn’t matter except at the connection points between wires. Unfortunately aluminum oxide is a poor conductor. It creates resistance in the flow of electrons and it results in heat being generated. If there’s enough heat, there’s a chance of fire.

To add to the problem, aluminum has a different expansion ratio than other metals commonly used in electrical systems. Repeated heating and cooling of connections where aluminum wire joins copper wire or another metal, such as under a receptacle screw terminal, can cause the connection to work its way loose. Once loose, oxidation between the formerly airtight connection now starts to build up.

There are products that have been developed to help deal with these issues. One is anti-oxidant compound that can be applied over the tightly twisted ends of the wires. It looks and feels like grease and blocks oxygen out of the joint to stop oxidation. Special aluminum-rated connectors or “Marrettes” should be used to join aluminum wires and aluminum to copper wires.

Terminal crews on components like receptacles and switches were improved to have more secure terminal screws. Of course these more specialized components come a significantly higher cost. To reduce cost, tradesmen have adopted the practice of “pig-tailing” the final connection. This means that regular components are used with a short “pig-tails” of copper wire which is then properly joined to the longer run of aluminum wire through the walls.

Aluminum wires in electrical panel

So if all this works, why do you still care about whether there’s aluminum wire in the house? One reason is that just the stigma alone may discourage buyers when you go to resell. On the other hand, if it doesn’t bother you there’s likely other buyers who don’t care either. There’s thousands of houses out there that are still happily standing with aluminum wire in them. Depending where you live another challenge might be getting insurance coverage. You are likely to pay a premium price when you find it.

So why don’t you just replace all the wiring with copper? The key question is how much it will cost. The major hassle is accessing those wires behind the walls. Bungalows with unfinished basements are the easiest to deal with since the electrician can get to most of the wiring directly. When you have to open up the walls and repair them things quickly get more challenging and expensive.

Hopefully this article has given you a better understanding of why Home Inspectors try to point out the presence of aluminum wiring in any house they inspect. You should have gained an idea of the impact that its presence may have on you. For some it’s and major issue and for others it’s barely a blip in the new home buying process.


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

Plain and simple, the purpose of a home inspection is to give you more information to base your home-buying decision on. The seller and their real estate agent will present you with the many features of the house. And it’s natural that they emphasize all the good qualities of the house. Home inspectors are there to help you identify major defects that they can find through a visual inspection of the property. It’s not that we want to be negative, we want you to see both sides of the property and make a choice with fewer surprises down the road.

Home to be Inspected

Most prospective home owners find their home inspections to be highly informative. You may be a first time buyers with maintenance questions, or need to understand the unique issues of country properties. We are happy to answer whatever questions we can while going through your property. Following along with us on our detailed inspection, you may be surprised by what you didn’t notice yet about your prospective new home.

Every house has defects. Usually a lot of small ones, but sometimes larger issues enter the picture. So what is a defect? Well, they can be a lot of things. Your inspector will be looking for things that aren’t as they should be. It might be a safety issue. It might be something isn’t functioning the way it should. There could be signs of past trouble or hints of future problems looming. While we can’t look at everything in such a short time, we do look at a great number of things. For a detailed list of the items I do and don’t look for see the Standard of Practice that I follow. If you get tired reading it all, think how much work it is to look at all that stuff. But don’t worry, the inspector does all that.

We just list the facts of what we find. The same defect may have great impact on one buyer and virtually none on the next. It depends on your needs and abilities. If you are already planning a kitchen renovation, that fact that the range hood doesn’t work might not matter very much. If your Dad owns a roofing company, old shingles are a lot less worrisome. You may not care that the electrical service is only 100 amp, but if you planning on getting a hot tub, it’s more important. So your needs and abilities can give you a much different perspective on the same house. Share your intentions for the property with your inspector so that he can take them into consideration.

At the end of the inspection, you will get a quick verbal summary of the findings, but wait for your Inspection Report before you commit to any firm decisions. It will have a write up of the defects found, many pictures and diagrams to explain them, and tell you when other resources are needed. It may call for further evaluation by a specialist or that contractor quotes might be needed. Read the report thoroughly, understand any risks with the property, and you will make a better decision. For more ideas on how you can get a better inspection read Tips for a Good Home Inspection

All the best on your search for the perfect new home for you and your family. What you learn now can help you have confidence in your residence.


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

1.The home inspector gives a pass or fail.
The inspector identifies defects in various components of a house. If the component does not function properly, demonstrates signs of pending nonperformance, or presents a safety risk to occupants and guests, the inspector will report a defect. This could be perceived as giving the components a failing grade but that is entirely different from deciding whether the house is the right one for you. Different clients can justifiably make different purchase decisions over the same set of defects. For example, if the clients have a family-member who is an electrician, even numerous electrical defects may not be material to them. The decision to buy or not always remains with the client. Pass or fail is up to you.

2. The inspector will look at everything.
Home Inspector
Inspectors budget their time to look at the most significant items in the home and only look at a sampling of some minor components. Other items are outside the scope of the inspection such as outbuildings, swimming pools and low voltage devices. We already have a lot to get through and you don’t have the time for us to exhaustively plod our way through every component on the property. We do look at a lot of items, the keyword being look.

3. Having an inspection removes all my risk.
Nope. Sorry. A home inspection is in no way a warranty or guarantee. Inspectors try to identify risks, or defects, for you. It helps you make a more informed decision when you buy. Hopefully we won’t find many significant issues but whatever we find, or fail to find, you accept the risk in our agreement and ultimately as the buyer. Assuming you still have an inspection condition, you always have the choice to walk away from the deal.

4. The inspector will tell me how much repairs will cost.
The best inspectors won’t. Remember that home inspectors are only allowed to visually examine a home. You don’t own the house yet. So we can’t open up the walls to see the extent of a problem. We will suggest when we think you should call a contractor to get some quotes. This works much better in the long run as you will have prices in place if you choose to proceed.

5. Inspections are all the same so lets just get the cheapest.
What you want is an inspector who is a graduate of a college home inspection program, belongs to a professional association of inspectors, is properly insured and is dedicated to providing you with the highest quality report possible. One or more of these critical factors is missing in the cheaper inspection services. They may try to race through the home and/or produce a shoddy report to save time. Be prepared to spend at least the average fee in the market if you want superior work. You are paying to find out as much as you can as part of your diligence. Why would you cut corners?

6. Inspectors are incredibly knowledgeable and invariably handsome.
This is not a myth. LOL. Inspectors are knowledgeable across a broad spectrum of house construction and maintenance practices. However we are generalists. When a specialist is needed, we will recommend you call one in; in much the same way a general practitioner will call for a medical specialist. Oh, and as for other thing, as Red Green might have said if clients don’t find you handsome they should at least find you handy.


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

At least in a manner of speaking. Everywhere we go we look for cracks in foundations. When we find them we try to classify them and evaluate the surrounding influences that might make the consequences better or worse. Cracks are a foundation’s way of relieving stress. The majority of houses offer one or more cracks for examination. So don’t panic at the sight of the first one. Let me offer a layman’s primer to the types of foundation cracks that may be encountered.

There are obviously ‘bad’ cracks that we refer to as ‘structural’. In inspector language, we might write, “the structural integrity of the foundation wall has been compromised”. What we mean is that the foundation wall is not doing its job of holding up the house properly. The damage is potentially significant and the cost of repair usually is too. The other thing to remember about a structural defect is that we are saying that the damage is going to get worse if you don’t get things corrected. If the foundation is not holding up the house in its original position, the weight of the house above will cause further stress cracks and movement. Don’t lose hope. Just because a crack is significant doesn’t mean that it can’t be properly repaired.

Inspectors look at the size of the crack, its orientation and for any displacement. The wider the gap the worse the crack. If you can get your fingertip in a crack, there has already been significant movement. A horizontal crack is generally of more concern that a vertical one because it suggests displacement. Displacement is when one side of a crack has shifted out of alignment with the other; the two sides are no longer in the same plane. Pressure from the fill around a foundation sometimes causes the wall to start to bulge inwards. Most commonly this happens with block foundations.

Buckling wall The picture shows a block wall that has started to buckle inwards. It has what we refer to as ‘step cracking’ as the mortar has opened between the blocks. The bulge displaces the blocks out of their vertical alignment and is often detectable by eye when sighted along the wall. Left unchecked further movement will cause the wall to collapse and the home will be unsupported along this section of wall.

The least expansive cracks are referred to as ‘hairline’ cracks. You can see them but the sides are still in contact and aligned. They are often located around basement window openings. Some cracks are caused by the tension in concrete drying out as it ages. Minor settlement can cause these too. If a crack has remained unchanged for years there’s less risk of future movement as settlement usually diminishes over time. The uncertainty is whether a recent crack will widen into something more serious. The pictures we put in our inspection reports can be a reference to refer to later. Wider cracks need special devices to help track millimeter size movements over time.

Cracks that we find in basement and garage floors are the least worrisome. It’s hard to find a house without them and unless the floor is buckling, or contains in-floor heating, inspectors aren’t going to get too worked up about them. In traditional house construction the floor slabs have very little structural significance. They are poured after the house is built and and the roof is on. They don’t play much of a role in holding the house up.

A non-structural crack that occurs in a well-drained, dry environment is pretty harmless. Once past the issue of structural support, the enemy we watch for is potential water intrusion. Concrete is not waterproof and the presence of cracks add to the potential to leak. Past leaks often leave signs and we will certainly comment if we find those. The influences I referred to earlier are things that either bring more water to the crack or fail to take water away from it. The grade around your foundation wall should slope away from the house. Landscape edging or porous fill like river rock can pool water along the foundation wall. The lack of an eves-trough on a roof surface above that drains towards that edge, or downspouts that empty too close can feed large amounts of water to an otherwise harmless crack.

I hope this article has helped to give you a better understanding of what Home Inspectors as thinking about while they look at a foundation wall. Ideally you now have some insight into distinguishing a serious crack from a lesser one.

Photos courtesy of AboveWater Foundation Waterproofing & Restoration Services Inc.


Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Red Flags for Buyers of Old Homes

Old House

Older homes have charm, character, and curb-appeal. Buyers tend to fall in love with them at first sight. Along with their beauty, older homes tend to need significant upgrades that can quickly gobble up household budgets. Not all old homes are money pits, but they all warrant a thorough home inspection. Old houses used the technology of the day and unless the previous owner upgraded key components, you are going to foot the bill sooner or later. Here are some things to think about before you write a quick offer.

Old houses have cellars rather than basements. They tend to have low ceilings and be damp; not a good combination for renovating. When foundation walls are made from rubble, stone or block not only are they likely to be damp but there are other potential issues. Significant cracks in walls and crumbling mortar are signs to watch for. If they have already been renovated, you may inherit mould or other issues behind the walls. Just keep in mind that cellars were not built to be living space.

Smaller electrical services are often found in older houses. The current just wasn’t needed back then, but it sure is now. Back then services were 30 amps. Now larger homes commonly have 200 amp service. If you see an electrical panel with fuses rather than circuit-breakers, you should plan on an upgrade. Homes built before the 1930’s can still have knob and tube wiring, hidden piecemeal behind walls. A couple of signs are receptacles mounted horizontally in baseboards, two-prong plugs and the ever-so-charming push-button light switches or ones with twist knobs. Upgrading requires more than electrical work, walls must be opened and refinished adding to the expense.

The plumbing system in an old house may consist of a series of retrofits cobbled together. It’s not uncommon to see cast iron, galvanized steel, copper and plastic pipes in one building. Cast iron and galvanized pipe work well for decades, but eventually rust on the inside and clog. Depending on the amount to replace, and its accessibility, repairs can be a major expense. Make note of their presence or absence.

Lead was often used for water supply piping. Some people consider this a major issue, others don’t see the risk. Just remember that if you buy a house with a lead pipe water supply, when you want to resell some of the buyers will be scared away. It’s expensive to dig up and replace the supply pipe to where the city service enters the property. After all that the city lines may still have some old lead pipe. Take a peek where the water supply enters the basement. If you see only copper pipe, the house has passed another quick test.

Fireplaces and wood-stoves were often the only source of heat in old houses. Somewhere along the line coal, oil, gas or even electric heat may have been installed. Lots of old houses still use hot water and radiators to distribute heat rather than today’s more common forced air systems. If the listing says natural gas forced-air heat with air-conditioning, you may have dodged another upgrade. Despite the charms of radiators and comfort of hot water heating, the house is less likely to have a central air-conditioning because the duct-work is hard to retrofit.

Original windows in old homes will be single-pane glass. When it’s all about the charm this may be a concession you are willing to make. Do make sure that the windows operate properly and are not painted shut. Double-hung window mechanisms can be repaired but the costs add up quickly. Older homes are less airtight and poorly insulated by today’s standard. Be prepared for a few drafts and higher utility costs. Make sure you see some bills.

Slate, cedar shake and cedar shingle roofs are stately features of any home and seem to look better with age. Be aware that the cost to repair or replace them are higher than today’s common asphalt shingles. If you see missing or broken shingles take note. While it may look charming, take special note of shaded areas that have moss growing on them. The less pretty name for moss is rot and it means repairs are probably overdue. While you are walking around the house admiring the roof-line and decorative trim, take a look at the chimneys. If they have a lot of character you may have some bills coming. Watch out for leaning stacks, missing bricks or mortar and cracks. As impressive as ivy covered walls appear, they grow by digging their tendrils into the mortar and may be doing damage to your masonry under that leafy facade.

The uniqueness and beauty of older homes can make them wonderful places to live and they are often in terrific locations. Knowing a few of the missteps to avoid can help you to sort through MLS listings quickly. I hope this article has opened your eyes to some red flags you can watch for when shopping for older houses. This is not an exhaustive list and is no substitute for a good home inspection. Here’s hoping that old house is your dream home.


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

A home inspection is an important part of your diligence in buying a home. Here are some tips to help you get the most value out of your inspection.

  • Start by finding a good inspector. Check your inspector’s qualifications. They should have completed a community or junior college program in home inspection and be a member of a professional association dedicated to home inspection. Try to stick to inspectors that only do home inspections. While real estate agents are aware of inspectors in the area and may provide referrals, an independent source may be advisable. Friends and relatives may know someone that they liked but you need an inspector that you have rapport with. You should feel that your inspector is interested in your questions and that you are comfortable communicating with them.
  • Once that trusting relationship starts out on the right foot, don’t undermine it by price shopping or asking for cash deals. Give as accurate a description of the house as you can. If you want to work with a professional, be a good client and respect the team members working for you.
  • Book a reasonable time for the inspection. Make sure you leave a little room before your condition expires for any other inspections or contractor estimates that may become necessary. Wells, septic systems, pools and wood-burning appliances are examples of specialized inspections that are frequently called for. You may lose control of the deal if you have to ask for more time to do them. There’s little point in starting after dark if you want your inspector to see exterior deficiencies. Most inspectors will work on weekends but most appreciate a free Friday evening. Statutory holidays aren’t popular either. It’s also a good idea to get the first inspection on the next available day rather than try to force a third one in on a busy day.
  • Review the inspection contract and standards of practice before you arrive at the inspection. It will help you to understand the service you are getting and avoids wasting time on site that could be better spent inspecting.
  • Good inspectors have a process that they follow to help them keep on track and cover all the things they need to look at. By all means ask questions but do your part to help keep things on track by asking questions in the room they pertain to.
  • Be ‘present’ at the inspection both physically and mentally. You are the client and the decision maker for your purchase. Make sure you are there so that you gain the most insight into the condition of the property. Don’t bring kids, relatives, leave pets in the car or carry on long personal phone conversations. It’s tempting to share the excitement and get input from others but there will be another time for that. During the inspection, anything that distracts you from seeing and understanding the potential issues with your new home is counterproductive. Worse yet, too many background conversations can get in the way of your inspector seeing everything you want them to find.
  • Don’t be a ‘Yabbut’! Some buyers are already so emotionally attached to the property that they get defensive when a defect is identified. If you jump in with a ‘Yeah but … my brother can fix that’ or ‘Yeah but … I don’t plan on using that bathroom’, you are not listening. Don’t debate the defects as they are found, you will have plenty of time to discuss the issues after the inspector delivers the report. Remember that you are paying for the inspector to find defects and that every house has them. You want to find out about them now so that you have options and can get estimates if needed.

Good luck with your purchase and I hope this has helped you get more out of your home inspection.


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

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