Bellingham WA Home Inspection (King of the House): Roofing Tar

The condition shown in the photo is not ordinarily seen by prospective buyers. Why? Because it is up on the roof where they dare not tread. When an inspector sees tar applied like this, it is a warning sign of amateur repairs. A real roofer uses tar more like glue - under materials to hold it down. In this case it is being used like a sealant or a dam.

Usually this type of application means one of three things, going from worst to lesser. (1) There was a leak and the homeowner raced to the home store and bought a tube or can of tar and slathered it. While that might have been a wise thing to do, as a stopgap, if he was getting major water intrusion, it is long term not a solution. An inspector should always look around the chimney, attic areas, to get any further clues as to this type of damage; (2) The chimney flashing was shot, loose, rusted or full of holes and the homeowner knew about it, went up and smeared tar around and about; (3) The chimney flashing was not shot, but the homeowner is not familiar with the proper design of step and counter flashings (they may not look watertight to the uninitiated who does not understand how water drains) so he slathered it just to be safe.

Tar liberally applied like this does not mean the roof is leaking, the tar might be working temporarily. But, even at best, tar will have to be re-furbished regularly as the sun kills it and causes cracks that will eventually leak. In the third scenario above, too bad the person wrecked the metal flashings -- the cracking tar may actually hold water and that makes a good flashing more prone to leakage than it was prior to the tar being applied.

Thanks for climbing on up here.

Steven L. Smith

Bellingham WA home inspections