The engineers of Carson Dunlop & Associates Ltd. have conducted over 85,000 home inspections and we haven’t found a perfect house yet. Since perfection is not an option, what should you expect?

The 1% Rule

When you consider the life cycle of every component of a house, a reasonable annual estimate of the cost of normal maintenance is 1% of the value of the house. One year you may replace the furnace; a few years down the road you may re-surface the roof. Throw in the odd unexpected repair in between and you average 1% per year. It’s incredible but this rule is not far off even for very expensive and very inexpensive houses.

Normal Maintenance 

If you strip away the cosmetics, a house is made up of the structure, roof, exterior envelope and the “systems” of the house. The “systems” are things like heating, plumbing, electrical and cooling.

All components and systems eventually wear out. Fortunately, they don’t all wear out at the same time. Different components have different life cycles. Houses tend to settle into what you might call a “normal maintenance pattern”.

What’s The Message Here?

A homebuyer should arrive at the home inspection with realistic expectations. If you are buying a 12-15 year old home, let’s face it, you may need a new roof covering. If you are buying a 60 year old home, you may have to update some plumbing. Don’t let this scare you away from a perfectly good home.

How Long Does it Last?

Here is a short list of typical life cycles of the most common components of the home. Please keep in mind that there will be exceptions in every category.

Roof

conventional asphalt shingles ……………………………………………………12 – 15 years
top quality asphalt shingles ………………………………………………………25 – 30 years
low slope shingles ………………………………………………………………….10 – 15 years
slate…………………………………………………………………………………….40 – 200 years
tar & gravel roof (built up roof)……………………………………………………..15 – 20 years
single ply roof membrane ………………………………………………………….15 – 20 years
roll roofing………………………………………………………………………………5 – 10 years

Exterior

gutters & downspouts ……………………………………………………………..20 – 30 years
copper gutters and downspouts …………………………………………………50 – 100 years
aluminum siding …………………………………………………………………….50 plus years
wood siding……………………………………………………………………….. maintenance dependent
stucco……………………………………………………………………………… maintenance dependent
exterior paint …………………………………………………………………………..4 – 6 years
deck…………………………………………………………………………………….10 – 20 years
asphalt driveway surface……………………………………………………………10 – 20 years
driveway sealer ………………………………………………………………………..1 – 3 years
concrete driveway………………………………………………………………………………..30 – 40 years
garage door opener……………………………………………………………………8 – 12 years

Structure

termite treatment …………………………………………………………………….10 – 20 years

Heat

conventional furnace …………………………………………………………………20 – 25 years
mid efficiency furnace ……………………………………………………………….20 – 25 years
high efficiency furnace…………………………………………..unknown, suspect < 20 years
cast iron boiler …………………………………………………………………………35 – 50 years
steel boiler ……………………………………………………………………………..20 – 30 years
copper tube boiler……………………………………………………………………..10 – 20 years
humidifier …………………………………………………………………………………5 – 10 years
electronic air filter………………………………………………………………………10 – 20 years

Cooling

air conditioning condenser ………………………………………………………….10 – 15 years

Plumbing

galvanized steel supply pipe ………………………………………………………………. 40 – 50 years
copper pipe …………………………………………………………………………………………. indefinite
toilet…………………………………………………………………………………………….. 30 – 40 years
sink …………………………………………………………………………………………….. 12 – 20 years
faucet…………………………………………………………………………………………… 10 – 15 years
whirlpool bath ………………………………………………………………………………… 15 – 25 years
shower pan……………………………………………………………………………………. unpredictable
submersible pump for well …………………………………………………………………. 10 – 15 years
suction or jet pump ………………………………………………………………………….. 10 – 15 years
water softener ………………………………………………………………………………….. 5 – 15 years
sump pump ………………………………………………………………………………………. 2 – 7 years
water heater…………………………………………………………………………………….. 8 – 12 years
tile bathtub enclosure ………………………………………………………………………. 10 – 50 years

Interior

paint………………………………………………………………………………………………… 5 – 10 years
windows ………………………………………………………………………….. maintenance dependent

Re-orders of any Carson Dunlop Report can be obtained by contacting our office. We invite your comments and suggestions of topics for future reports.