Vinyl Siding
Inspecting a home with vinyl siding is like looking for “Home Inspector Treasure”. If the home has multiple roof lines where soffits end in the side walls and a chimney that is also vinyl sided, there are even odds I will find a significant defect. If the home is vinyl over old hardboard siding, like “Masonite”, and it has multiple roof lines, the odds of finding a significant defect under the vinyl are nearly 100%.
Why?
The main reason is the installer did not follow the manufacturer or the industry guidelines for installing flashing. It’s really simple to understand. The siding is the surface of the exterior wall. The surface should be installed so that any water entering into or under this surface should be directed back to the surface of the siding. That’s done with flashing!
We typically see one of three scenarios.
New construction has begun to rely on a house wrap that is taped around the windows. Water that gets under the siding is supposed to flow down the house wrap and drip out the bottom. Unfortunately we frequently see there are gaps in the house wrap in the same areas there should be flashing or even knife cuts across the wrap somewhere down the wall. We also see the house wrap stops a few inches before it gets to the bottom of the wall. So that drip from above runs down the wrap and soaks into the OSB board near the base of the wall.
On homes just a couple of years old we frequently see the vinyl siding applied over the OSB board with no house wrap. The code said it was OK but I have never found manufacturers that recommend this method. The code must assume proper flashing but then no one ever checks to verify the flashing was installed. On a home with multiple roof lines ending into side walls, you will have problems. We’re finding blackened OSB board from moisture entry and we’ve had drought weather for years. What will these look like when it starts to rain again?
The third is my favorite! Vinyl over some old hardboard siding. Much of the time this siding was applied more like paint than siding. It was just used to cover up the old siding. With no new flashing for the vinyl siding, water flows under it and wets the old siding. Since the old siding was being covered over there was no need (so it was told the homeowner) to replace all of the rotted siding. The old soft hardboard siding soaks up the water and holds it longer because it is now under the vinyl.
Water in walls is always a bad thing! The wall sheathing like OSB board or the old siding starts getting wet. Before long a rotten spot shows up and the decay begins to work on the framing behind the sheathing. Gravity forces the moisture to work down the wall closer to the ground where a variety of things live that love moisture. Before too many years you have a wall full of wet wood and millipedes or worse, termites.
What should you do?
Most home inspections, including ours, are limited to what is visible from the outside. I can tell you that kick out flashing was not installed but there may be diverter flashing under the siding. A moisture meter may help, if there has been rain recently, but will not work with the foil covered paper wrap that was popular for many years. An infrared camera might be nice to have but again is very limited depending upon weather conditions. The best way I have found is just to go to the most likely bad areas and look under the siding. This can be very time consuming on some homes so we now offer this as a separate inspection. If there are just one or two areas we include that in our standard inspection.
One more often overlooked water source is the sprinkler heads in your yard. Vinyl siding will not prevent water entry when it is sprayed upward onto the siding. Frequently the lower edge of the OSB board sheathing will be rotten because the sprinklers have been spraying onto the exterior of the home.
1. Adjust your sprinklers so there is no water spraying onto your siding
2. Inspect for and correct any installation defects or damage
3. Clean your siding when it gets dirty
4. Trim shrubs and trees away from the siding
5. Do not place a heat source (like your grill) any where near your siding. The siding will warp and sometimes even melt and run down the wall.
Bill
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Together we provide the unique dual perspective of a husband and wife team. Our philosophy is simple. We treat people the way we would like to be teated and we treat every inspection like we are buying the home.
