Quality Roofing is in the Details

Roofs on North Texas Homes are mostly sloped roofs built with a wide variety of materials. Clay and cement tiles, steel panels and shingles, Rubber tiles, asphalt shingles. wood shingles… the list just goes on, BUT our task on this page is to cover the fundamentals that all reliable sloped roofs require. Be aware that each type of roofing material has its own work specifications. Make sure your roofer follows those specifications.

Reliable sloped roofing relies less than you might think on the quality of the choice of roofing materials you see on the roof. Roofing material manufacturers have developed reliable products. The key to reliable roofing depends on how the roofing materials are put in place.

Now you don’t see these details in the finished project, so you can inspect how they were placed. All you see then, is the finished surface appearance. Oh, you can see the outline of shingle seams to know they were put down in order, you can see that there are order to the step flashings around a chimney or along a sidewall; but the inner workings- how the step flashings and the layer of underlayment are interwoven, how the valley flashing assemblies are created- determines whether your new roof will be reliable of will have mysterious leaking problems.  Will the quality of your next roof depend on trust, or on your system of verification of the construction process?

There are two key factors to a long lasting and reliable roof.

1. Quality materials that meet spec and

2. the workman-like way these quality materials are layered together as per the work specification. These details will help you understand that not all roofers are equal, or that just calling yourself a roofer does not mean much.

You need a roofing company who fosters a roofing crew who cares about quality and cares about the customer long term. You also need to remember, the dapper lad who sells the roofing is not the person who comes out in the hot sun to do the work. There is a disconnect here sometimes. Good roofers support and nurture great roofing crews.

Before going any farther, you might want to look at some basic roofing mistakes to avoid. These are a big deal, and they blend right into what is being stated next.

These details are significant because so many problems on roofs relate to cutting corners with the specifications. Roofing transition areas require good judgment and care to make sure the roofing materials are laid down properly in an order that sheds water properly.

There are a few water shedding fundamentals that you need to understand.

They spell the difference between reliable roofing and mystery gravity defying leaks. – yes, that is sarcasm.

We have to understand overlaps and end laps and where water can end up.

shingle roof application specification for the field

The shingle roofing specification underlines our point about overlaps and end laps. The top overlap covers the lower sheet so water always runs over the top edge and never against a lap edge. This seems simple but get into tight construction spaces or around protrusions, and  the principle can be lost. Slope transitions and corner cuts must be carefully shingled together. Good workmanship with quality roofing materials make a reliable roof. Quality roofing materials can be abused and leave you the homeowner feeling abused.

This same shingling of materials together what make chimney flashings work and side wall transitions work. We will look at a sidewall specification next. We will save chimney flashings for their own page.

specification for a tile roof side wall flashing

A properly shingled side wall flashing assembly insures that water running down the adjacent wall does not outflank the flashing system on the roof. This is a side wall flashing specification for a concrete tile roof. Every type of roofing material has components that deal with the same fundamental challenges that fit the need of the roofing material. The text of the article will describe the critical components here.

There is a lot going on in the above sidewall flashing image, we are just going to concentrate on the side wall portion. The edge of the roofing ends in a channel flashing into which water is channeled downslope and off the drip edge of the roofing.  Do you see the inside raised edge of the channel? Water is not allowed to divert back onto the underlayment.

The wall side then extends up the wall. The drainage plane of the wall then sheds water from the wall over this outside edge of the channel flashing. We cover the drainage plane of the wall in greater detail, that is the water control layer of walls, separately.

But we must mention that cladding is not considered a water control layer, it is the weathering and protection layer. The pretty yet reliable wearing layer.

The above diagram designates a vapor retarder layer or an underlayment but does not show detail. This underlayment is the moisture control layer and when water penetrates the cladding it is stopped by the underlayment and is allowed to dry from air circulation in the gap between the underlayment and the cladding. More details in the link for keeping water out of walls.

OK, now you will see a couple images where these principles have been forgotten and water penetration is occurring. This is why we are talking about fundamentals here. We do not want you buying pseudo solutions like these.

image of a wood shingle sidewall matched against shingle roof.

OK, so someone thought that a little asphalt patching compound was the answer to a leaking problem along the wall. Now all the water behind the wood shingles cannot run off but is trapped into the structure. Cladding is not totally water resistant.

image of counterflashing tacked on over a brick sidewall

Bricks are not totally water resistant. Someone is breaking the fundamental rules of building construction. Water works it way through bricks and either drains away through weep holes or just dries out in the air gap between the brick and the wall sheathing. This is a brick veneer over some kind of sheathing. So any water which penetrates the brick here is captured inside the wall somewhere, where it can rot wood, destroy sheathing or grow mold.

These shingling principles are the fundamental method for keeping rain water out of your home. We deal with potential water leaks in the macro here.

We have to understand the problem with transitions in roofing elevations.

We just talked about the basic sidewall transition but home designs meant to catch the eye often create roof transitions that catch water rather than shed it off. Then we also have problems with penetrations through the roof that are not really placed properly and roof additions that complicate roofing badly.

 

We have to understand proper workmanship.

Water coming in through the roof usually shows up around chimneys, along valleys maybe, around skylights, or protrusions, roofing sidewall drip edge transitions. These are the transition areas. Roofing can be complex, and Texas weather is punishing. Quality roofing is not a trivial matter in Texas.

You can run into basic design flaws in homes in North Texas. These can complicate your roofing assembly.

1.  Many homes in North Texas have a variety of sloped roofs which transition into each other. These create complications.

These types of roofs require details which demand low slope design specifications, even flat roof – waterproof roofing design specifications. to give the house a reliable roofing assembly.. These kinds of roofing issues are included in what we call “at risk” homes- on this website and we talk about them here. 

2. Roofs leak because we abuse them with additions to the roofing which are poorly designed and constructed.

Skylights are wonderful but they add complexity which often turns into problems. Skylights are discussed here.

Adding penetrations to the roof multiplies your risks for leaking problems.
antennas,  Christmas lights, solar thermal hot water heating panels, solar panels, all require fasteners to secure. Fasteners create holes in the roofing assembly. Fasteners also compress and, therefore impact the slope of the roofing materials. Water runs off according to gravity and the lowest adjacent area. Water can run sideways when roofing is compressed or obstructed. This is problematical.

Compressed roofing assemblies and hardware relating to roof additions can impede water runoff or direct water over and around these added penetrations. Roofing materials also stretch and shrink from thermal radiation according to the temperature change coefficient of the materials. These materials are then worked around these fasteners. Roofing materials pull away from fasteners and create pathways for water to enter. These factors all come together to enhance the risk your home has for water leaks through your roof.

Remodeling? Has your roofline changed? New additions can change the slope or change elevations.
I have even seen valleys cut into to accommodate new building elevations. These kinds of changes multiply potential problems because elevation changes can greatly complicate the design of the roofing assembly and demand patience and expertise from the worker on site. Elevation changes can require sheetmetal smithing skills, flat roof assembly skills as well as flat roofing materials, and then the usual materials and skills required to deal with the standard sloped roof.

Plumbing stacks or bathroom vents can be placed to close to sidewalls or other penetrations. We must be ready to redesign critical design failures on roofs. We do not want non-standard configurations of protrusions on roofs. Pipe clusters can end up right against walls. Everything needs proper clearances. Quality roofing specifications require proper clearances.

Bad things Happen to Roofs in North Texas and we can plan for them.

Does your home have a basic prominence as to wind? Are you high on a bluff or is your roof exposed directly to wind? Proper roofing designs here should include high wind specifications. You want your next roofer to understand high wind fastening standards.

We can even go to a class 4 shingle and get a break on the insurance. Class 4  is a hail resistant shingle that just might keep you out of the roof replacement business when the hail comes and you can watch all your frantic neighbors stressing out while you know you planned ahead.  We talk about class 4 shingles here.  LINK

What are your thoughts on the subject? Do you have a question? Maybe a thought to add to the discussion.

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