Q&A – Lifespan of a tar roof

Buying a new home is a big investment, so this buyer wanted to get some expert advice before making a decision.

James from Pennsylvania was looking to make the big choice to buy a new place, but wanted some advice about what he was possibly getting into, so he asked:

I am interested in a purchasing a home that has a metal roof (in Ohio). However, the metal roof is fully covered with tar. The owner states the tar needs to be redone every 4-5 years. Is that a normal or common roofing system? I'm concerned that there are underlying issues and they're simply covering everything up with tar. Or that the weight of the tar will be an issue over time. Please let me know if you have any thoughts or concerns. Thanks!

James' question got multiple answers from our roofing experts! First, John Kenney of Cotney Consulting Group said:

Looking at your attached photo, it appears the roof panels have been in place for many years and either rusted through or had the fastener back out, and the fix was installing whatever type of coating sealer was installed. It does not appear to be a good candidate for continued applications. I recommend you remove the panels and install a new system that will last many years for you.

Another expert, Shawn Snodgrass from Kalkreuth Roofing and Sheet Metal, also responded:

Anytime a coating has been used on a residential roof, the original roof likely has already run out it’s life span. Coatings are not recommended by any of the metal roof manufacturer’s and voids any warranty that may have been in place at that time. Furthermore, I would not recommend coating a metal roof with any asphaltic product as they have a tendency to run when temperatures rise, filling the gutter with tar. I would also not recommend coating a metal roof multiple times as there in no way to determine the total weight as it relates to how the home was constructed.

I hope this helps.

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