Concrete Tile Roof

Concrete tile roof – Overview

Today’s concrete tile roofs, cement tile roofs and clay tile roofs are rarely installed according to current known and best practices in the Lower Mainland Area. What I mean by that is ideally one should install a tile roof system over top of a sheeted and waterproofed layer of plywood. This is rarely done due to the costs associated with this degree of waterproofing. We commonly see an underlayment sheet, draped over trusses with 1×4 cross straps nailed over top of that. These cross straps are hopefully spaced accordingly to allow for a 3” head-lap between rows. A good salesman calls this underlayment draping a waterproofing, but that is giving it far too much credit. If it is a waterproofing why is there all these nail holes in it and why are the vent protrusions not sealed to the vent pipe? In some cases it is an organic cardboard which will deteriorate and rot over time and in other cases it is just a thin sheet of polyethylene (clear plastic) which only lasts a couple years until it dries up and disintegrates. Simply put – the underlayment is merely a stop draft addition and should not be given much credit as a membrane.

If I was to build a house and wanted to put on a Monier or Columbia tile roof system, here is what I would do. Sheet the rafters, making a deck surface of ½” plywood and H-clips. Install a peel and stick waterproofing system. There are many acceptable products to choose from by every manufacturer known. Ensure that, at this layer, I am 100% watertight at all transitions, protrusions and terminations. Now, install 2×2 runners up the existing rafters followed by gridding your roof using 1×4’s and allowing for the required 3” head-lap suggested by manufacturers. Your tiles can now be installed.

The finishing details would be as follows – I want to use a 26 gauge drip edge flashing at all rake and gutter edges. All tiles in contact with a hip shall be cut accordingly and fastened to the 1×4 strapping or the hip rafter so as to not fall out of place, or slide down, as is too commonly witnessed in the Vancouver area. I want lead cover patches on all my multi-tile intersections. I want containment lips bent on all my galvanized vent flanges. I want gooseneck vents used to ventilate my attic space. I want lead stacks for my plumbing vent pipes. I want to use 26 gauge metals on my valley flashings. And finally I want to use a pan flashing network around my skylights and grind out the underside of the tiles so they don’t compress the containment lip over time.

If you’ve got a concrete, clay or cement tile roof and want an assessment to learn what needs to be done to reduce the probability of leakage, contact Crucial Roof Services at your soonest convenience.

EPDM membrane bridging

Staying with the topic of EPDM membrane hidden gutter systems I would like to touch on the topic of membrane bridging. This evolving deficiency occurs on almost all rubber gutter systems. It is due primarily to the fact that the gutter itself was merely loose-laid into the trough and not chemically adhered to the wooden substrate with a bonding agent. Through the lifecycle of the rubber, it dries and shrinks and becomes in non-contact with the underlying deck. This shrinking action results in the pulling-away from the wooden deck and a bridging of the membrane.

The bridging primarily affects the desired water flow of the system to the drain. When a membrane bridges, it causes a rise in the level of the rubber and sometimes builds an obstacle that the water cannot bypass to get to the drain. The end result is a gutter that constantly holds water. This is not an extreme issue of concern if the gutter is installed according to today’s accepted practices. Where this becomes an issue is if the initial installer’s workmanship is failing. Standing water plus poor installation details commonly result in an accelerated fascia board and soffit rot problem.
Extreme cases of membrane shrinkage result in water overflow down the fascia boards instead of the intended flow through the drains and downspouts. Membrane shrinkage can also cause poorly sealed seams to tear apart and become water ingress locations.

Resolution of such bridging problems can be brought about by adding additional drains at critical points or cutting out the extreme bridge locations and patching the resulting cut/hole with appropriate and compatible rubber products applied with accepted and proper means.

If you notice standing water, fascia board and/or soffit damage and are concerned about the cause, contact Crucial Roof Services for a free consultation and estimate.