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Go With What You Know

Approximately 90% of all structural building failures are caused by moisture. With the exception of the homeowner, moisture is the #1 enemy of the house. Unfortunately, moisture damage typically occurs in concealed spaces. This makes it difficult for most home inspectors to identify.

Good inspectors know there are 3 major elements that impact the risk of moisture intrusion.

  1. The more complex the design of the home the higher the risk.
  2. Poor drainage of water on or around the house increases the danger.
  3. Missing or improper flashing details can be a disaster.

Based upon the analysis of these 3 principles, an experienced inspector will determine whether the probability of concealed moisture damage is low, medium, or high. Regardless of what other ‘experts’ may say, home inspectors are required to communicate these observations to our client and make the appropriate recommendation.

Let me give you an example. Within the last year I inspected an Italian Renaissance home with an elaborate and complicated building design. This building included numerous room projections from the main structure, a 3rd level tower, and a traditional stucco exterior finish.

A flat roof deck was incorporated within the main hip roof structure that included a large skylight and an internal drainage system.

Flat Roof Deck & Skylight
Internal Roof Drain

The perimeter of all windows, doors, band boards, and corners had ‘bump out’ projections without any flashing. Doors onto the flat roofs were level with the deck and had no room for threshold flashing. The stucco was extended below grade without any drip screed flashing. And the roof did not include kickout flashing.

Bump Outs With No Flashing
No Kickout Flashing

Seemed like a no brainer…complex house design, poor roof drainage, and missing flashing details made this high risk. However, the home had been previously moisture tested by a very reputable contractor. The infra-red imaging and meter probing results were all negative. The ‘expert’ concluded no to low probability of moisture intrusion.

Should a professional home inspector change their conclusion and recommendation? Absolutely not, go with what you know. In this example my clients relied upon the moisture testing, moved into the home and quickly discovered the exterior wall structure was rotted out, the house was unsafe to live in and would require over a half a million dollars to fix.

Always remember…STAY WITH WHAT YOU KNOW…an inspector is paid for their opinion not someone else’s.

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI Certified Inspector, ACI
Kaplan University, Home Inspection Lead Instructor

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Let’s Look Closer At Deck Failure!

There are just two basic reasons for decks failing. The first is overloading and the second is improper construction.

Overloading: deck failure usually happens unexpectedly. We have been using the deck for several years, even barbecuing for the family without a problem. But today we are having a graduation party. Fifty teenagers’ crowd the deck which has never carried more than seven people! The music starts, the teenagers jump up and down, and the deck tears off the rim joist with the deck collapsing towards the house. Unfortunately several people are hurt.

What happened? Floor loads in a house are limited to 40 pounds per square foot or a point load of 300 pounds. That limit is designed to carry some furniture and people walking or sitting in the room. Decks are usually designed to the same limit so our deck was grossly overloaded with a large number of people on it, and absolutely could not carry the extra shock load of the teenagers’ dancing . The reason the deck failed where it is connected to the house (or the rim joist) is that this is the point where the entire load is perpendicular to the direction of the fastener. It is like suddenly smacking the fastener with an ax.

Party on the deck, by all means, but have it checked for structural integrity to be sure that the extra load can be carried. Pay particular attention to the rim joist, which should be bolted in a manner that pulls the deck floor joist and the house floor joist together. Proper hardware and an installation guide are available from your local big-box store.

Improper construction: every existing deck should be inspected to see that it has been properly constructed. Unfortunately, many contractors and local building officials do not appreciate that proper deck construction is even more important than it is in a house. The deck at some point will carry greater loads than the house floor and is being continually attacked by the weather where it has to contend with sun, rain and snow loads.

Any home inspector can determine if your deck is capable of carrying the loads required. Most often a contractor will be able to reinforce the existing structure without the need of building a new deck.

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI certified inspector, ACI
Kaplan University, Home Inspection Lead Instructor

‘Pops’ Rob Leslie
Kaplan Professionals, Retired

 

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Wood Deck Failures

What happened to pressure treated deck lumber?

Pressure treatment is a process that forces chemical preservatives into the wood. The wood is placed in a closed cylinder and pressure is applied to force the preservative into the wood. Preservatives protect wood from decay and insect damage. There are 3 classes of wood preservatives; the waterborne method is typically used in residential construction. For decades the lumber industry successfully used CCA, chromated copper arsenate, as the preservative of choice. However negative publicity regarding the arsenate caused the wood product industry to voluntarily transition away from CCA to alternative preservative systems. CCA has no longer been used residentially since December 2003. A number of alternative preservatives are available. The most recognized are ACQ, alkaline copper quad, and CA, copper azole.

Testing has indicated that ACQ and CA are more corrosive to steel and the protective coatings applied over steel.

In other words, the old galvanized nails, screws, metal hangers and connectors were no longer approved for use with the ‘new’ pressure treated wood. Unfortunately, either nobody told the builders and lumber suppliers or they just didn’t care. Hot-dip galvanized or stainless steel fasteners and hardware are the recommended products to use. The structural stability of the wood deck depends upon using these approved fasteners.

When you see rusted nails, bolts, and other metal hardware on a wood deck, it is a big problem.

 

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI certified inspector, ACI
Kaplan University, Home Inspection Lead Instructor

‘Pops’ Rob Leslie
Kaplan Professionals, Retired

 

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Decks Can Be Dangerous

Deck failures are becoming more common. Why do decks fail?

The most common reasons are:

  • Old age
  • Poor design
  • Improper materials
  • Overloading

Decks should be inspected annually. All lumber should be inspected for rotting, particularly where posts meet the ground, at joist unions, and the ledger board connection to the house. Most of this rotting is caused by old age, moisture, and lack of maintenance.

However, much of the rotting is coming from fasteners and connectors that are incompatible with the type of wood preservative the deck lumber was treated with. Rusted heads on nails, screws, or bolts connecting metal joist hangers are an indication that these fasteners or connectors have failed. This was caused by a chemical reaction between the metal hardware and the pressure treated wood. This form of failure is the number one reason for decks collapsing.

Unfortunately, there is great confusion as to which fasteners and connectors are to be used with what type of lumber. The best choice is stainless steel, but it is also the most expensive and difficult to obtain. The most commonly used nails, screws, bolts, and metal hangers are hot dip galvanized. These are a good, available, and lower cost choice. The thicker the galvanized coating the better and longer the metal hardware will perform. Other approved materials, similarly priced to hot-dipped galvanized, are silicon bronze and copper.

Deck collapses are often related to overloading or lateral movement. This two conditions place a great amount of stress on the deck fasteners and connectors. Therefore, whenever rust is seen on nails or screws, they should be removed for inspection or replaced.

Avoid a disaster inspect your deck each year.

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI certified inspector, ACI
Kaplan University, Home Inspection Lead Instructor

‘Pops’
Rob Leslie
Kaplan Professionals, Retired

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Too Much Roof Snow?

Can my roof collapse from too much snow load? It’s possible, but highly unlikely.

Since about 1950, cold climate states must adhere to engineering principles that configure the structure of the roof. They are based upon the highest potential roof snow load in your area. The building code will then require the roof be designed and sized to safely meet or exceed those live snow loads. In Minnesota that load is 42 pounds per square foot north of a line that crosses the state just south of Hinckley. The south side of the line which includes Minneapolis and St Paul is 35 pounds per square foot.

How deep would the snow be if there was 35 pounds of snow per square foot on the roof?

Well…if it was light snow it would be 5 feet deep! If it was medium or normal density it would be 2.5 feet deep and if it was tightly packed, it would be more than 1.5 feet deep. The measurement by the way would be uniform over the whole roof. In the real world there will be places that are less deep or less dense. These include areas that are covered by roof overhangs, spots protected from wind, and behind chimneys and dormers. So, if your roof meets current code, you have little to worry about.

However, if your home is hundred years or so old or you have some reason to doubt that it has been built to code, you may wish to remove some snow. Remember though, if you are removing snow you are removing a very good insulator.

If you must remove snow use a roof rake with extension handles. Never stand on the roof or scrape the roof bare as this may damage the shingles. Be very cautious about letting someone who comes knocking on your door remove the snow from your roof. Check their credentials. Make sure they have insurance.

This could become a very expensive mistake!

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI certified inspector, ACI
Kaplan University, Home Inspection Lead Instructor

Rob ‘Pops’ Leslie
Kaplan Professionals, Retired

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Your House Cracks

Home Inspectors get paid a lot of money every year just to look at other peoples cracks; cracks in plaster walls and ceilings, cracks in basement and garage floors, cracks in foundation walls.  To understand cracks the first thing a real estate agent or homeowner need to know is that almost all plaster and concrete cracks.  Seasonal changes in air temperature and moisture levels cause building materials, wood and concrete, to expand and contract.  Have you ever heard strange house noises that you didn’t recognize or couldn’t locate?  If so, it’s just another ‘house whisper’.  This type of movement is small and will typically have no long term impact on the building.

So when is a crack significant?

Seasonal movement cracks will range in width of 1/8 to 1/4 inch.  They will be consistent in size for the length of the crack and there could be more than 1 in the same location.  These cracks can be vertical, diagonal, horizontal, or in a step pattern.  It is very common for these cracks to be located near windows, doors, vaulted ceilings, basement floor posts and beams.  These cracks are aesthetic and mean absolutely nothing to the stability of the house.  Normal movement cracks probably make up about 98% of the cracks real estate agents and homeowners will typically see.

Structural movement cracks are different.  They are big, 3/8” or greater is size.  Many times these cracks are wider at one end than the other, in other words they are tapered width.  Sometimes one side of the crack will not be on the same wall or floor plane as on the other side of the crack.  This is uneven when a section of the wall or floor has moved but the other section didn’t.

Not comfortable with what you are seeing…

Uneven or differential movement is not OK and these cracks require close scrutiny by a ‘qualified’ and certified home inspector.  These experts will be able to ‘listen’ to what these cracks are saying and determine the next steps to pursue in correcting the problem.

Doug Hastings
MN Home Inspector, Minneapolis & St. Paul
ASHI certified inspector
Kaplan University, Home Inspection Lead Instructor

Rob ‘Pops’ Leslie
Kaplan Professionals, Retired

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