Multiple Layers of Shingles? Not a Good Idea. Here's Why...

Hi Michael, you have written another very informative blog post, thanks for the information.

What I get after reading this decent posting is that engineering has the final say

Hi Michael - I need to keep you out of east Nashville. Some of those 80 year old homes probably have cedar shingles under all that.

We use all tile roofs here in Arizona. Only the felt underlayment has to be replaced after 10 years or so.

Correct!  It is a band aid fix, and more money in the long run to add layers!

Hi Michael Thornton ....Great Advice!

Cheers, have a fun and successful day!

Thanks for these valuable tips, Michael.  Good information we can share with homeowners.

Great advise Michael! In our home inspections, we always look to see if there is more than one layer of roofing and report it if there is. We also check to make sure that the underlayment comes out over the top of the drip edge as well as lots of other items. A homes roof covering and roof structure are crucial to long term performance. Thanks for posting!

Michael, I have always hated(and still do) that practice. Another thing is that is the only time you get a real good look at the decking to make sure all is well there. 

Hello Michael ... great post and VB knew many years ago when I helped family re-roof their home. Never put new shingles over old shingles

Michael I replaced my roof 4 years ago, and even though I only the original layer of shingles on my roof, I had the Roofer take them off so that the new shingles would be the only layer.  It only cost a few hundred more and was well worth the price.

Those are all sound reasons for one layer of shingles.

Michael, if the layer being replaced shows excessive wear then there's a good chance the under-layer of wood has been compromised and it needs to be addressed

Michael Thornton - that's something new I learned.

I used to think that an additional layer would increase the life of a roof by few more years but after reading your post, I think that's not right thing to do.

I always have wondering what inspectors like yourself had to say.  Thanks for this informative post.

I have seen three layers on one house. This was wrong and I kept thinking about the extra weight.

I was unaware of why you should not have more than two layers of shingles. I know it is cheaper and easier for the roofer. In the long run it is costlier for the homeowner.

Michael Thornton, I like the idea of a single layer of shingles better than two layers as well.  

There were more reasons than I realized. Very helpful advice we can pass along to homeowners. 

This is an excellent post. Thank you for sharing and best of luck!