Roofblog

 Recently I was asked why I would recommend that a house be equipped with both ridge vents and gable vents, in addition to soffit vents, for the purpose of ventilating  the attic space of a house. It has been suggested by some professionals in the roofing industry and roof ventilation manufacturing industry, that having both ridge vents and gable vents installed on the same roof area would be detrimental to the performance of the ventilation system. I disagree with that idea and suggest that having both ridge venting and gable venting, although possibly weakening the system slightly in a specific situation, would enhance the system overall.

Let’s take my house as an example.

I live in the Lake Erie snow belt of northeastern Ohio. We get on average over one hundred inches of snow fall per year.

 If this house had only soffit vents and ridge vents, and in the middle of winter those ridge vents were closed off because they were covered with a thick layer of snow, my attic would not ventilate properly. Heat would build up in the attic, ( heat will rise into the attic from the living space, you can’t stop it, you can only slow it down ), the heat would warm the roof and the layer of snow next to the roofing, the snow would melt and water would run down to the eave and cause an ice dam. The ice dam may cause a roof leak and the heavy ice could cause my gutters to be torn from the fascia. If I had GAF shingles on my house the warranty would be immediately voided because the ventilation system had become un-balanced.

Now, if I happen to have gable vents installed in addition to the ridge vents, when the ridge vents are covered with snow my gable vents will still perform and exhaust the hot air from my attic, eliminating the negative effects

But what if the ridge vents are not covered with snow? Won’t the gable vents “short circuit” the ventilation system?

Many roofing contractors and homeowners are concerned about the so called “short circuiting “ of the ventilation system balance. The idea is that on a breezy day, wind will flow perpendicularly over the ridge vent. The low pressure created will then draw the warm air from the attic to be replaced by cooler air on the outside of the house. If there are gable vents, or other vents installed on the roof, the replacement air will be drawn from those vents instead of the soffit vents. And the hot attic air will remain in the attic. I don’t agree with that assessment for the following reasons:

1. Hot air rises- the hot air in any attic will find its way to the attic peak and any cooler air will settle lower in the attic. Therefore, the hot attic air will be exhausted from the ridge vent whether the replacement air comes from the gable vents or from the soffit vents.

2. Cold air sinks. Any cooler air introduced to a hot attic will flow to a point below the hot air.

3. Ridge vents are not power exhaust vents. They do not draw massive amounts of air quickly through the attic. Cold air drawn into an attic through gable vents is drawn in slowly and will sink below the hot air and help to push the hot air higher into the peak of the attic.

  Now this whole scenario is based on there being a rectangular house with a gable end roof and the ridge located perpendicular to the flow of the prevailing wind.

What would happen if we take that house and roof and rotate it ninety degrees so that the breeze and airflow is parallel to the ridge and soffit vents. For this example there are no gable vents.

In this case:

1. high pressure builds on the windward side of the gable.
2. the airflow is displaced around the house and creates low pressure on the ridge and sides of the house.
3. low pressure is created on the leeward side of the house.

Now the low pressure created on the sides and ridge of the house draw air from the soffit vents and from the ridge vent. If those vents are balanced, ridge exhaust equaling soffit intake area, then the low pressure will draw equally from both ridge and soffit essentially canceling each other out. The hot air stays in the attic.

If we then install gable vents:

1. the high pressure on the windward side of the house pushes air into the windward gable vent
2. the low pressure on the leeward side of the house draws attic air from the leeward gable vent.
3. the low pressure along the sides and ridge of the roof draw what air they can
4. the attic is ventilated

Note; The preceding is based on basic house architecture and simple wind modeling. There are too many variables such as and not limited to: actual house structure, location, the surrounding environment such as trees and lakes, prevailing wind and atmospheric conditions etc. Add to that the unknown effects of turbulence as air passes over the non-aerodynamic surfaces of a house.

It is my humble opinion that the ventilation system for a roof and attic be designed and installed to fit the particular house that is being worked on, and not a cookie cutter venting system designed for a house that was built in a factory and has no resemblance to real life roofing or construction conditions. It is also my opinion that no one ventilation system will perform perfectly in all situations. Again, there are too many variables (seasonal weather changes, homeowner lifestyle, building maintenance, etc.) for a ventilation system to work one hundred percent of the time with one hundred percent effectiveness.

More roofing pictures,contractors and information at RoofersReview.com

Well it’s that time again. The end of winter and that drip, drip, drip you’re hearing isn’t just the sound of the icicles dripping onto the sidewalk. It’s the sound of a roof leak and water dripping from above your window frame onto the window sill.  It’s a roof leak that you can’t repair and there’s nothing you can do about it.

Well there are a couple things you can do. First, relax. You’re house is not going to melt. Get a couple buckets and towels and place them under the leaks. Next, call a roofer.

And try to find a roofer who has been in business for more than a few years. They tend to have a little more experience with the next steps. The next step is to remove some of the snow from the roof. It isn’t necessary to climb on the roof to do this though. From a ladder against the roof, the snow can be pulled off with a snow rake. Care must be taken to not damage the roofing material.

Here, a snow rake is being used to remove about a foot and a half of snow.

After some of the snow has been removed the water behind the ice dam should be visible. In the valley areas ( where most ice dam roof leaks occur ) the water can be quite deep.

This is a close up of a slate roof  with an ice dam. This is the valley, about two feet up from the gutter. The water here is about three inches deep and running under the roof slate and leaking into the house.

If you have a major leak problem and have found a qualified, experienced roofer. Some of the leaking and water backup can be alleviated by cutting a channel in the ice dam for the water to run off the roof. This is more dangerous than removing the snow and can result in more damage to the roof and gutter. Ice chopping should only be done by a professional.

After some of the water has run off the roof, sidewalk ice melter granules can be spread to help melt the rest of the ice dam. Be careful of the type of ice melter and what it may drip on below as it may stain.

It is now time to think about scheduling a roof repair for the spring. Attic ventilation, insulation, possibly new underlayment for the roof should be on the agenda.

More roof repair information and roofing pictures at RoofersReview.com.

Why do I have both ridge vents and gable vents?

I live in Chardon,  snow capital of Ohio,  part of the Lake Erie snow belt. We average over 100 inches of snowfall a year. It can snow two feet in one day, or two inches every day for a month. Temperatures can range from 60 degrees to a balmy -5 degrees, usually within a week.

Combine the heavy persistent snow fall with fluctuating temperatures, sunny days and freezing nights, and you have the perfect recipe for ice dams and roof leaks caused by water backup.

This recent snow storm covered my roof with six to eighteen inches of snow. Blanketing the metal roof  ridge vents, and the “mushroom top” attic vents of the shingled roof.

Snow covered roof and vents.

Normally this would cause the warm attic air, ( the warm air that is supposed to stay in the living space but because the house is so old it loses much of it’s the heat to the attic and leaks out through the old windows and doors ), to remain in the attic, warming the underside of the roof, causing ice dams and water backup and leaking into the house around the front windows on the south side of the house.

Yes, it’s happened before. But now, even with the ridge vents covered with snow, the gable end vents will still exhaust that warm attic air, leaving me roof leak free.

Roof gable vents.

Of course there are experts who claim that with both ridge vents and gable vents installed, the ridge vents will only draw air from the gable vents and not the soffit vents, leaving the warm air in the attic. If that were the case, I think I should install exterior wall vents near the ceiling of my living room and a power vent in the ceiling to the attic, then the outside cold air would flow through the room straight out the ceiling vent and the warm air from the furnace would wrap around my feet as I type.

More roofing pictures and attic ventilation information at RoofersReview.

It’s been nine years since we opened the front door.

Guess it’s time to do something about that.

And so here is the part where we’ve torn off the siding, repaired the foundation sill, the corner boards, the door sill, etc. And it’s time to scrap that ugly entry roof and trim.

It’s odd, I specialize in roofing old houses, slate and copper roofs and gutters, and always do the best job possible for the customers. But, when it comes to my own house, I just want to get the job done. For as little money as possible, as fast as possible.

Maybe it’s because I still have to finish installing the siding, paint the siding and trim,replace the windows, strip and refinish the door and hardware, etc. And winter is coming and I have too much client work to get done before it snows.

My plan never works out. I start out intending to measure and fabricate the copper on Friday night after work, and knock out the roof first thing Saturday morning. But the wife and kids have other plans and I don’t get to the fabricating till Saturday mid morning. And when I start the installation the drip edge isn’t exacty right so I have to go back and re bend it. And the solder joint isn’t perfect, and in another hundred years the next roofer might see that and think I was a lousy tinner, so I re do the joint.

In the end it turned out fairly nice, just more time consuming and more expensive than I intended. Like every other project on this house.

For the rest of the story and more detailed pictures of the copper roof installation.  

Roofing and roof repair information and pictures at RoofersReview.com .

It was just my opinion, based on personal professional experience, concerning the economic ramifications of repairing an old slate roof versus replacing same in my last post. But it is the customers opinion that counts. And the customers opinion was that the old slate had enough charm and added something to the asthetics of the house to warrant keeping and repairing the slate roof.

Even though it may have been close to half the cost of replacing the roof with new asphalt shingles, the homeowner opted to keep the old slate roofing material and just replace the stack flashing and repair the damaged slate shingles. The remodeling contractor removed the old pipe and lead flashing and installed new plumbing and a new PVC soil vent pipe through the roof. The contractor also supplied the aluminum and neoprene flashing as a lower cost alternative to a new lead full pipe flashing. Depending on the amount of exposure to sun the neoprene flashing receives, it should last fifteen to twenty years before the collar will need to be replaced or re sealed. As long as there is no storm damage, or careless painters walking on the roof, or other incidents, the slate roof should also last another fifteen to twenty years. Maybe longer.

There are more examples of both poor and good roof repair work at RoofersReview.com.

Often I come across a slate roof that’s just not worth repairing.

 Today I received a call from a local home construction contractor asking if I could give an estimate on installing a new pipe flashing on a plumbing stack he was replacing. He was remodeling a bathroom in a century home nearby.  After a cursory inspection of the roof it was decided to replace the stack flashing and also the cast iron soil pipe. The lead stack flashing looked like it was the original and was in terrible shape and there had already been prior repairs.

 The roofing slate is soft low quality gray slate. The slate material itself is wearing out, spalling and delaminating. The repair that needs to be done, replacing the soil stack and installing new flashing, would also require replacing about 9 pieces of slate around the pipe. The original workers drove nails through the flashing flange and through the slate. Each of the slates now has a hole or is cracked and will need to be replaced. The cost of that repair alone would run about $350. But there are also other repairs that need to be done. There are numerous broken slates and quite a bit of damage caused by the gutter installers. The gutter crew drove nails right through the slate to secure the gutter hangers.

Where the slate was not immediately broken, it was damaged enough to be weakened and later broken by heavy ice on the eave.
Besides the slate, it is evident that the roof has been leaking for some time, so there is also a good chance of deteriorated rotted roof decking under the slate that will need to be replaced.
Now once all these repairs are made and the roof is sound, there is still soft old low quality slate on the roof that is still deteriorating and could fail at any time. It’s just not worth doing the repairs and trying to save the old slate roofing. For the cost of the repairs, this roof could be replaced with a decent quality asphalt roofing material, or for a little more a new slate roof could be installed.

There are more slate roof repair examples and roofing information at RoofersReview.com

More slate roof leaks , in my experience, are caused by the roofing contractor and or roofer, who was hired to repair the roof after the original roofing material wore out.

This is a picture of a botched slate roof repair.

Here is a slate roof that is about 80 years old near Cleveland, Ohio. Normally a slate roof will be leak free for as long as the metal flashings hold up and there is no breakage of the slate. The original flashings on this house were copper sheet metal. After about 60-80 years of water running down the valleys or dripping off the slate the copper will wear through and develop a leak. The holes will always be in the center of the valley at the crease, or along the edge of the slate line. So when the roof starts to leak the natural thing to do is call a roofing professional to repair the roof. In this case the homeowner was unwilling to pay for a qualified reputable roofing contractor, or, the roofer that was hired was unqualified and misrepresented his abilities. Either way, he caused more problems.

The picture shows a slate roof that has had it’s valley flashing replaced. The new metal is a thin aluminum sheet metal. The light gray slate is what is called a “short slate repair”. This was done because the roofer was too cheap or lazy to go out and buy the right slate for the repair. They used whatever was readily accessable, whether it was a piece they had in their own stock or a slate they picked up at a salvage yard. The original was a 22 inch long Vermont green/purple S1 quality slate. The replacement was less than 20 inches long and a low quality soft gray slate. Installed as is there is no headlap, or coverage, under the slate course above. They tried to compensate for this by inserting a small piece of sheet metal between the slate courses. This may work temporarily at keeping the rain out, but in an area that receives a lot of snow, this repair will not protect the roof from ice and water backup.

 There are more slate roof repair examples and roofing information at RoofersReview.com

Use the right materials to do the job properly.

A common mistake of inexperienced roofers is not having, or knowing what material is needed to properly repair a certain type of roof.

This is a picture of a slate roof with a plumbing vent pipe that has had it’s flashing boot replaced. The brackets on the roof are being used to access and repair an upper roof section. The previous roofer has used an aluminum pipe flashing for the replacement of an older, likely worn out lead flashing. This aluminum flashing is generally used for the replacement of flashings on lower pitched asphalt shingle roofing. As you can see by the buckled metal and poor fit, it was never intended for this type of roof.

Here we have  slate roofing that has been repaired near the edge of a roof valley section. These slate were fastened with electro galvanized steel nails. The slate is good quality Vermont slate that will likely last for another 75 years. These steel nails were installed less than ten years ago and already are rusting away. The galvanized plating is just too thin to handle the moisture conditions on a slate roof.

There are more examples of both poor and good roof repair work at http://www.roofersreview.com/.

Tar on slate. Temporary at best, likely to cause more problems at worst.

Roof repair _ Tar on slate roof

In this case the original roof was installed with tin sheet metal used as flashing along the roof dormers. The thin metal flashing probably lasted 60 yrs before it rusted away and the roof began to leak.
Here, the roof repair was made by spreading tar along the roof slate and dormer slate intersection. Covering over the rusted tin flashing.
This may slow down the worst of the water leak, but will not eliminate the water intrusion.
Wind driven rain can still enter the house at the dormer wall above the tar from between the slate joints. Also it will not take long for the tar to dry out and crack, allowing in more water. This may just be a little, and not enough to show up in the house on the ceiling. But, it will be enough to soak the roof boards and rafters and cause much more damage in rotted wood.

The right way to repair the roof would be to remove the slate shingles and replace the rusted tin flashing with new flashing. Preferably copper.

Wandering around the internet I found a roofing contractor in Chicago that specializes in ornamental copper roofing. Conrad Roofing has been in business for over 55 years.

Check out this brick and stone house with copper roofing and gutters. That’s a standing seam copper roof on the conical roof over the entry. Each pie shaped segment is cut and bent in the sheet metal shop before being brought to the job site. Then the individual pieces are fastened with hidden clips to the roof decking and the standing seams are folded together to make a water tight roof.

At the peak of the roof is a custom fabricated copper finial that does a beautiful job of matching the roof lines. And the bottom of the roof has a custom made copper radius gutter to keep the rainwater in it’s place.

Behind the conical copper roof is a large transitional area where the three roof planes meet. Sometimes called a valley cricket, it is covered with  soldered flat seam copper roofing. At the peak of the lower ridge is a stone chimney flashed and counter flashed with sheet copper.

Conrad Roofing Co. is located at  5122 N. Elston, Chicago, IL 60630
Tel: 773 282.5131 Fax: 773 282.3208