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My 33 years in the building science business has involved air barriers, waterproofing, and flat & steep slope roofing systems.

Experience in the area

My roofing encompasses commercial systems (BUR, mod-bit, single-ply) and residential applications (asphalt shingles, cedar shingles, slate and metal. I am cognizant of code stipulations in regards to FM and UL for commercial roofs.


Attended numerous courses offerd by Roof Consultants Institute, Roofing Industry Educational Institute, Factory Mutual Research Corporation, University of Wisconsin, and BURSI. Lectured for RCI and mentored at a local university for a Building Science Certificate.

Past/Present Clients

Government, commercial businesses such as The GAP, hospitals, school boards as a roof designer.

What do you like about this subject?

Always learning something new as I can never say I know it all.

What do you still hope to achieve/learn in this field?

Share my roofing knowledge with those who will benefit from it.

Average Ratings

Recent Reviews from Users

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    K = Knowledgeability    C = Clarity of Response    P = Politeness
susan02/09/16101010Thanks again! I will contact your friend .....
Kevin Tucker09/01/15101010Thank you very much for your prompt .....
Kevin Tucker08/31/15101010Thank you very much. I am fixing .....
rose01/18/15101010Thank you

Recent Answers from D. John Henderson

2015-08-31 Flat roof:

.1- 3 rolls of base sheet / 6 rolls of cap sheet approximately  .2- Do not know how competent you are. I did a friends carport with a self-adhering two ply about the same size and it took me two days and

2015-08-29 Flat roof:

I assume this roof is over a portion of your home that has insulation under the roof deck (batt insulation between the roof joists above the drywall ceiling).    Since this is an occupied space the most

2015-08-25 Leaf guard?:

There are various types of gutter guards available.  Some are a metal screen, foam insert that fills the gutter and lets water in and nothing else, curved metal cover that allows water to run in but leaves

2015-06-11 Flat roof maintenance.:

The roof is small so I assume you have no Laps or joints in the membrane.. The membrane should easily last 20 plus years  Coatings are available for EPDM membranes.  Search the web under EPDM membrane

2015-05-20 Venting front porch:

You have not given me enough information to even attempt to formulate an answer.  I assume the following:  The front porch soffit is not part of the house and there is no insulation in place between the


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