The Home Inspection Professionals in Binghamton, New York

Members of the American Society of Home Inspectors. Proudly serving the Southern Tier of NY and Northern Tier of PA since 1989.

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1278 Vestal Avenue
Binghamton, New York   13903

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Serving Broome, Tioga, Chenango, Cortland, Tompkins, Susquehanna and Bradford Counties

A Roof Framing Warning

Gregg Harwood, Professional Home Inspection Service

You are in a twenty year old neighborhood and you pull into the driveway of a nice colonial with an open porch which runs across the entire front of the house. This porch is constructed of a six foot deep concrete floor with two story wood or aluminum columns supporting the eaves of the gable roof. Are you with me? This style of house invariably also has an attached two car garage. We see quite a few of these houses in the nicer neighborhoods. The Realtor will say that this house has great "curb appeal", however, warning bells should go off to the home inspector!

I have inspected two of this style of home in the last six months with the same roof framing defect. The problem involves "spreading" of the conventionally framed rafters (not trusses). In order to create the front porch the builder frames a roof with a total span equal to the width of the house plus the depth of the porch. The rafters bear on the rear exterior wall and on a header supported by the front porch columns. A short knee wall ( cripple wall, jack wall) is then built from the top plate of the front wall to the underside of the rafters. This roof will spread because the base of the rafters are not tied together. No "roof triangle" has been made. One house I inspected had collar ties installed and it had still spread.

This movement can be very hard to spot. You may not notice that the tall columns are a couple of inches out of plumb, especially if they have a built in taper. The best way to check these roofs is to sight the knee wall to see if it is true and plumb. This involves crawling on your belly in the fiberglass insulation, but it is necessary to confirm the condition. Another indication of trouble you may spot is a separation in the porch ceiling finishes or trim, either at the front wall or at the column header.

I believe that the best way to re-enforce this type of roof is to sister on two by sixes to each ceiling joist to extend out to the rafters. This will create the same rafter/ceiling joist triangle which stabilizes most conventionally framed roofs. Another option may be to install diagonal braces from the top of the knee wall back to the ceiling joists. If you encounter this defect the advise of a PE may be warranted.

Other defects to check for include deflection on the header, decay at the base of the columns, and settlement of the porch footer. Be careful out there.