Roofing question

[GN4WHLN]

It's about the time to replace the roof on our house and I'm not sure which way to go here. Our home is in So Cal so we don't have snow loads, or extreme cold. We are probably going with another composite shingle roof but where I'm not sure what to do is with flashing and venting.

We have had a couple of roofers not want to use flashing in the valleys and instead use what they term a "California Valley". They say it is less likely to leak. Others say flashing is the way to go.

The other issue is venting. When it's warm, I get air coming out of the eaves instead of the roof vents. The attic is very hot and has several areas where it feels like there is no circulation. I was thinking of adding some dormer vents to allow better venting of hot air and some of the contractors that came out thought that was a good idea. One guy that came out said he would like to ridge vent the whole structure. That looked interesting to me. It seems like it would vent the structure better.

Can anyone tell me what the pros and cons are with any of this? Is there anything I should know or consider?

 

[58Yeoman]

The house I built in 1974 had a full ridge vent, and the house I'm living in now has full ridge vent. I like it better than the little 'turtle' vents, as I think it looks better and probably does a better job.

Being born in 1950, I like the flashing better than the overlapped shingles...again, it's my personal preference.

 

[johnnyradiant]

Up a little past Seattle a lot of places have had more success with metal valleys. If those valleys pick up a fair bit of water on a steeper pitch those are likely some of the first shingles to fail. Now in So Cal water erosion will be low on the totem pole.

Continuous ridge vents offer good ventilation but it is equally important that your soffit vents are good throughout. In our community we are quite wind protected (I'm not sure how that factors into the equation of other areas) - a lot of homes use the whirly roof vents to boost circulation as well. I don't think I would be too keen on one on my roof if I lived in a really windy area or one that gets a few high winds a year. My first hand experience with the dormer vents is that they don't have good penetration in terms of circulation. My roofer (I normally have 2-3 roofing jobs for him per year) also says they don't work that great on most roofs. I think it is because they just circulate with the close soffit vents rather than try and trade air all the way across the house to the vent on the other side = dead spot in the central part. Here the old houses with dormer vents normally get ridge and or whirlies to get the air venting throughout.

 

[ard]

1. A California Valley is cheap and fast. Eliminate sheetmatal, eliminate cutting two shingles per course.... creates a weak spot in the roof, place for cracking of the shingle

2. Ventilation is all about square inches of ventilation. For your location and attic size there will be a recommended venting number.... Ridge vents have a published 'sq in per linear foot'. Use that, match that to the soffit vents. Add dormer vents if the ridge is inadequate

3. Anyone talk to you about radiant barrier? Pretty sure CA requires minimum roofing radiant barrier even with re-roofs. Some sheating has radiant on one side. It will reduce your cooling costs, dramatically if done right.

4. Whole house fan to **** air up out of the home, into the attic and out the attic vents is a great way to cool overnight. You also keep the attic cool, reduces AC costs/loads. Cheap. 200-300 and a saturday to install, for a builder grade one from HD.

 

[GN4WHLN]

1. A California Valley is cheap and fast. Eliminate sheetmatal, eliminate cutting two shingles per course.... creates a weak spot in the roof, place for cracking of the shingle

2. Ventilation is all about square inches of ventilation. For your location and attic size there will be a recommended venting number.... Ridge vents have a published 'sq in per linear foot'. Use that, match that to the soffit vents. Add dormer vents if the ridge is inadequate

3. Anyone talk to you about radiant barrier? Pretty sure CA requires minimum roofing radiant barrier even with re-roofs. Some sheating has radiant on one side. It will reduce your cooling costs, dramatically if done right.

4. Whole house fan to **** air up out of the home, into the attic and out the attic vents is a great way to cool overnight. You also keep the attic cool, reduces AC costs/loads. Cheap. 200-300 and a saturday to install, for a builder grade one from HD.

My feeling was the California valley was a cheap way to do it.

I like the ridge vent and it seems to be the way to go. I'm going to find out about the radiant barrier. Right now, it's all planked. should that be removed and replaced with OSB or plywood? I've thought about that and the whole house fan. That seems like a good way to drop our AC use in the hot part of the year.

It's going to cost a few bucks to do this so I want to make sure I get it done right.

 

[GN4WHLN]

Up a little past Seattle a lot of places have had more success with metal valleys. If those valleys pick up a fair bit of water on a steeper pitch those are likely some of the first shingles to fail. Now in So Cal water erosion will be low on the totem pole.

Continuous ridge vents offer good ventilation but it is equally important that your soffit vents are good throughout. In our community we are quite wind protected (I'm not sure how that factors into the equation of other areas) - a lot of homes use the whirly roof vents to boost circulation as well. I don't think I would be too keen on one on my roof if I lived in a really windy area or one that gets a few high winds a year. My first hand experience with the dormer vents is that they don't have good penetration in terms of circulation. My roofer (I normally have 2-3 roofing jobs for him per year) also says they don't work that great on most roofs. I think it is because they just circulate with the close soffit vents rather than try and trade air all the way across the house to the vent on the other side = dead spot in the central part. Here the old houses with dormer vents normally get ridge and or whirlies to get the air venting throughout.

I'll have to make sure we have adequate venting under the eaves. I know that attic has some big dead spots in it.

 

[GN4WHLN]

The house I built in 1974 had a full ridge vent, and the house I'm living in now has full ridge vent. I like it better than the little 'turtle' vents, as I think it looks better and probably does a better job.

Being born in 1950, I like the flashing better than the overlapped shingles...again, it's my personal preference.

Flashing in the valleys and a ridge vent seems to be the consensus.

 

[Davefr]

I would never allow a California Valley. (at least here)

The valley will accumulate debris like leaves, needles, etc and you'll need to clean that area frequently. If you don't, the debris will impede rain run off and soak in the moisture. That can also make it a prime location for moss to form.

A metal valley will have less friction and debris will have a much better chance of sliding down the valley and being washed right into the gutter.

If you have minimal rain and/or no overhang from trees then it might not be that big an issue.

 

[ard]

... about the radiant barrier. Right now, it's all planked. should that be removed and replaced with OSB or plywood?

No, not needed. But adding radiant on the underside of the planks is more of a PITA.

Just ask your contractors "are you getting a permit?", then see what tehy say about radiant

I've thought about that and the whole house fan. That seems like a good way to drop our AC use in the hot part of the year. .

Oh, it is astonishing. I have 40+ days a year over 100F. But almost every night it drops to 65 or less. Open a window, fan on- instant cooling breeze.

GL

 

[matt_i]

My opinions are
- use metal 'W' valley flashing. It takes more time but I think is a better job and longer lasting because it won't wear out. The underneath "corners" of the shingles should be clipped and then also sealed with a dab. The W-flashing should not ever be nailed to the deck, it should be held in with nail-heads or better yet metal tabs that are nailed but hold the flashing in by friction. I also would place ice + water shield in the valleys below the metal flashing. Its probably not something that's sitting on the shelf in your area. I think Grace makes a high-temp version of the peel + stick for use under the potentially higher temps of metal roofs. I would get that.

- Use ridge vent, but it must be matched by an equal cross-sectional area of soffit vent. I put in the GAF Cobra ridge vent.

- I prefer the synthetic woven underlayment to tar paper. I think its tougher and amazingly water resistant. Grace and GAF have it to name a couple, I think there are many competitors.

Here's the "clip" detail I used. I lapped the valley flashing 12".

 

[850xpeps]

Ya ice and water and the metal flashing gets my vote. Ridge venting is useless in a snowy climate. But won’t matter to you so it will work good for you. Also make sure you have gable end vents they will help out as well.

 

[matt_i]

Ridge venting is useless in a snowy climate.

Curious about why you feel this way.

 

[850xpeps]

Clog with snow dust. My roof is one example of it not working. The warm air condenses and freezes them up. Have seen other roofs with same effect. I won’t waste my time installing them on a shingled roof. My roof is tin as well an they still don’t seem to work.

 

[ard]

FWIW- I have all hip roof on the house, and as a result very short sections of ridge- hence I needed to add dormer vents. By choosing to place these is low visibiliuty areas that are not visible from main road, entrance, pool/patio, you can reduce the visual impacts. All high up near the peaks, combined with continuous soffit vents.

It snowed here 9 years ago....

(hence- no grace snow and ice )

Oh, I also installed a few hundred feet of 'roof to wall vent', where I had shed roofs over the first floor running into the wall of the second story. Creates a nice clean detail, allows air to likewise enter the soffit, exit the top of the roof where it hits the wall.

 

[dave_dj1]

Clog with snow dust. My roof is one example of it not working. The warm air condenses and freezes them up. Have seen other roofs with same effect. I won’t waste my time installing them on a shingled roof. My roof is tin as well an they still don’t seem to work.

Then you have an insulation problem and not a venting problem. The attic should be the same temperature as the outside air. It should not be full of warm moist air in the winter. My advice is to add some attic insulation for starters, make sure you have adequate vents whether soffit/ridge or larger gable vents.

OP, you have received some good advice above. We use the woven valley's here in the northeast all the time and I have never seen an issue with debris, leaves, gravel or anything else sitting in them and clogging them up. I believe it's a personal preference on woven vs metal.
As long as you understand the need for air flow and follow the math for it you will be fine.

For anyone that wants/needs to vent a hip roof and doesn't want to look at metal dormer vents you could always do eyebrow vents, they look sharp if done properly.

I know you all don't know me but I have been in the building biz for 40 years, owner of my own construction co. for the past 25 years.

 

[850xpeps]

Then you have an insulation problem and not a venting problem. The attic should be the same temperature as the outside air. It should not be full of warm moist air in the winter. My advice is to add some attic insulation for starters, make sure you have adequate vents whether soffit/ridge or larger gable vents.



OP, you have received some good advice above. We use the woven valley's here in the northeast all the time and I have never seen an issue with debris, leaves, gravel or anything else sitting in them and clogging them up. I believe it's a personal preference on woven vs metal.

As long as you understand the need for air flow and follow the math for it you will be fine.



For anyone that wants/needs to vent a hip roof and doesn't want to look at metal dormer vents you could always do eyebrow vents, they look sharp if done properly.



I know you all don't know me but I have been in the building biz for 40 years, owner of my own construction co. for the past 25 years.

I’m also a builder. It isn’t a lack of insulation. My ceiling is r50 lol my attic isn’t the only one with this issue. Your experience and mine might differ. This is mine with ridge venting. My insulation stops are in place and my soffit is well vented including the large part that’s 4 feet wide by 12’. There is an issue of inadequate venting caused by the vented ridge. It’s on my entire house and by so ft including soffits is sufficient.

 

[dave_dj1]

I’m also a builder. It isn’t a lack of insulation. My ceiling is r50 lol my attic isn’t the only one with this issue. Your experience and mine might differ. This is mine with ridge venting. My insulation stops are in place and my soffit is well vented including the large part that’s 4 feet wide by 12’. There is an issue of inadequate venting caused by the vented ridge. It’s on my entire house and by so ft including soffits is sufficient.

How big is the house? The ventilation may not be adequate.

 

[Handyfarmer]

when I have roofed I put down a tin valley and (making sure I do not puncture the valley tin) , and weave the shingles over the tin, been doing this for nearly 40 years building, and have not had problems,

 

[rburke65]

How can you have 'inadequate ventilation caused by vented ridge'? Can't wait to hear this....

 

[ddawg16]

Where GN4 lives.....snow is NOT a problem

I've done my own roof....and know quite a few people who do that work.....

Valley Flashing....only way to go. Some of the guys touched on it correctly....The valley see's the most volume of water....if you don't have metal, it just wears out the shingles there faster.

You can't have too much vent....assuming you also have good insulation.

How many vent opening (soffit vents) do you have? You should have a 3x10 opening about every 10' or so....or closer. Dormer vents are good. Most of your wind comes from the same direction....unless the Santa Anna's are up. You kinda want to have to opening of the dormers so they are downwind....it helps to **** the hot air out.

The new thing now is the synthetic underlayment instead of tar paper. But good tar paper still works.

Most important....do NOT settle for a roof over. Do a tear off....i.e., they tear off all the old roofing material. This lets you inspect for any damage and repair it....and it kinda forces you to replace all your drip edge....which is a good time to clean and paint the fascia boards.

I would also suggest dimensional shingles....looks a whole lot better.

When I did mine, I asked the guy if I should go 30 or 40 year shingles....his comment..."After 25 years you are going to be tired of looking at that roof".

I went 30....still looks great. I did it about 15 years ago and I'd be surprised if it needed to be redone sooner than 15 years from now.

BTW....I know a good roofer....not sure if he wants to go out your way....it's about 60 miles from him.

Otherwise, I would suggest going to your local roofing supply and asking them for references. They know who is good....the good ones stay busy and buy the right materials.

 

[redneckcharlie]

There is absolutely no difference in the quality of the roof nor the warranty given by any of the major shingle manufacturers as to if there is an exposed valley flashing or not. To get there full warranty’s it’s based on using a certain number of their products to get their full warranty. Owens corning for example is four products here. I only use their dimensional shingles. Done literally hundreds of roofs over the years, haven’t done an exposed valley in 25 years. Personally I don’t lke the look of it. With a dimensional shingle the exposed metal takes a way from the roof appearance in my opinion. Do what you want, you’re paying for it so the decision is yours. Doing an overlay on an existing roof is perfectly acceptable if the existing shingles are in a condition to do so. Code allows two layers for a reason. An overlay here is 200$/sq where a full tear off and replacement is $400/sq. We have some of the worse roof conditions in the country. Elevation is a mile, the uv is brutal. Our temperature swings can be 50 plus degrees. Tonight itll be 20 and over 70 tomorrow. The current class of shingles are very good products.

 

[ddawg16]

There is absolutely no difference in the quality of the roof nor the warranty given by any of the major shingle manufacturers as to if there is an exposed valley flashing or not. To get there full warranty’s it’s based on using a certain number of their products to get their full warranty. Owens corning for example is four products here. I only use their dimensional shingles. Done literally hundreds of roofs over the years, haven’t done an exposed valley in 25 years. Personally I don’t lke the look of it. With a dimensional shingle the exposed metal takes a way from the roof appearance in my opinion. Do what you want, you’re paying for it so the decision is yours. Doing an overlay on an existing roof is perfectly acceptable if the existing shingles are in a condition to do so. Code allows two layers for a reason. An overlay here is 200$/sq where a full tear off and replacement is $400/sq. We have some of the worse roof conditions in the country. Elevation is a mile, the uv is brutal. Our temperature swings can be 50 plus degrees. Tonight itll be 20 and over 70 tomorrow. The current class of shingles are very good products.

Your screen name seems appropriate.....

Your right....no difference in warranty....but it is prorated....here are a couple of links that discuss the pros and cons

https://www.uexpress.com/first-aid-for-the-ailing-house/2012/10/1/metal-valleys-on-roof-are-the

https://www.iko.com/na/blog/pro-tips/open-roof-valley-vs-closed-valley-roofing/

Code might allow 2 layers.....but Owens Corning has a different 'opinion'. Which might impact that warranty....

I personally think a roof with 2 layers looks like ****. Closed valleys look even worse.

In the morning I'll take a pic of my neighbors house done closed valley last year and my house with valley flashing.

PREPARATION
A. Prepare surfaces using the methods recommended by the manufacturer for achieving the best result
for the substrate under the project conditions.
B. Remove all existing roofing down to the roof deck.
C. Verify that the deck is dry, structurally sound, clean and smooth. It shall be free of any depressions,
waves, and projections. Cover ALL holes 1 in (25 mm) or less in diameter, cracks over 1/2 in (13 mm)
in width, loose knots and excessively resinous areas with minimum 28 gauge; 0.0187 in (0.475 mm)
galvanized steel, 0.0156 in (0.396 mm) stainless steel, or 0.0126 in (0.320 mm) aluminum sheet metal.
Decking or deck boards with holes greater than 1 in (25 mm) in diameter shall be replaced.
D. Replace damaged deck with new materials.
E. Verify installed roof deck is acceptable to receive shingles. Acceptable roof decks include the
following:
1. Wood boards: 6 in (152 mm) minimum width, 3/4 in (19 mm) minimum thickness.
2. Plywood sheathing: 3/8 in (9.5 mm) minimum thickness Exposure 1 grade plywood sheathing
as recommended by APA and in compliance with local building code requirements.
3. OSB panels: 7/16 in (11.1 mm) minimum thickness non-veneer structural panels as
recommended by APA and in compliance with local building code requirements.
4. Spacing between boards or panels shall not exceed 1/4 in (6.4 mm) between roof boards or 1/8
in (3.2 mm) between plywood or OSB sheathing panels.

 

[dave_dj1]

How can you have 'inadequate ventilation caused by vented ridge'? Can't wait to hear this....

I don't want to sidetrack this thread but imagine a house that is 50-60' long and 40' wide, lot of attic and maybe not enough vent. FYI those soffet vents plug up with dust and paint. Maybe they didn't use proper vent at the eaves, Who knows, I'm just trying to point out possible causes for the attic to be moist and warm in the winter. Could have penetrations in the ceiling insulation. I don't know, I haven't seen the house. I do know that the attic should not be moist and warm in the winter months.

 

[850xpeps]

How big is the house? The ventilation may not be adequate.

1450 sqft main floor with 572 sq ft attached garage kept at around 12 degrees Celsius. House is kept at 19-21 depending on time of day and if the wife is cold lol

Soffit makes up about 508 sqft of area. Gets cleaned every year. Roof is a t shape where garage comes off front. So would be 3 gable ends but they are also half hip. So small gable mostly hip. All ridges vented. Maybe 80’ vented ridge on tin. Big vent opening. The snow dust blocks the ventingfor the most part probably causing any moisture that eventually closes it. Before I blew in insulation I cleaned around light boxes and added poly and sealed them.

 

[rburke65]

Sounds like not enough vents.

 

[Falcon67]

A paper I found that may help -

http://www.bestmaterials.com/PDF_Files/Vent-calculations.pdf

I'm considering doing the roof on our house. The valleys are like most - underlayment, flashing down the valley and a "weave" - one run of shingles crosses the valley, then other coming from the opposite direction overlays the others and gets trimmed just off center of the valley.

 

[GN4WHLN]

Where GN4 lives.....snow is NOT a problem

I've done my own roof....and know quite a few people who do that work.....

Valley Flashing....only way to go. Some of the guys touched on it correctly....The valley see's the most volume of water....if you don't have metal, it just wears out the shingles there faster.

You can't have too much vent....assuming you also have good insulation.

How many vent opening (soffit vents) do you have? You should have a 3x10 opening about every 10' or so....or closer. Dormer vents are good. Most of your wind comes from the same direction....unless the Santa Anna's are up. You kinda want to have to opening of the dormers so they are downwind....it helps to **** the hot air out.

The new thing now is the synthetic underlayment instead of tar paper. But good tar paper still works.

Most important....do NOT settle for a roof over. Do a tear off....i.e., they tear off all the old roofing material. This lets you inspect for any damage and repair it....and it kinda forces you to replace all your drip edge....which is a good time to clean and paint the fascia boards.

I would also suggest dimensional shingles....looks a whole lot better.

When I did mine, I asked the guy if I should go 30 or 40 year shingles....his comment..."After 25 years you are going to be tired of looking at that roof".

I went 30....still looks great. I did it about 15 years ago and I'd be surprised if it needed to be redone sooner than 15 years from now.

BTW....I know a good roofer....not sure if he wants to go out your way....it's about 60 miles from him.

Otherwise, I would suggest going to your local roofing supply and asking them for references. They know who is good....the good ones stay busy and buy the right materials.

Hey John,

So yeah, no snow here. This house only has one gable and it is very shallow because there is a vaulted ceiling below. We do have a 3X10 at least every 10. The house does have a lot of ridgeline for venting. I'll talk to the roofer about whether it is adequately vented at the eaves. Right now the attic gets really hot (Like 125-130) on a warm day but that seems to be due to a lack of exit for the heat.

I know currently there are two layers, so we will be removing it all for exactly the reasons you stated. I want to be sure the new roof is done right with all new materials and the structure below is in proper shape. We'll probably sell and move after we retire in 6-8, so I want the house in good shape when that comes. Mechanicals and function come first. If I need to add vents, that's going to get done.

If we need dormers, I can put them on the south side as that sees less wind than the north. We live in the foothills along the south face of the San Gabriels and the Santa Anas can really blow through here at times.

I am going to add some blown-in insulation in the attic at some point. What's there is not in real good shape, but it seems like I am always in the attic adding to the wired part of our network or doing something electrical. I've already added the plastic runners the keep the insulation from blocking the eave vents, so as soon as I think I'm done up there, I'll see about blowing some insulation in.

I always ask my friends at Garage Journal first because I know I'll get some great feedback from people who have done it or are professionals.

 

[GN4WHLN]

A paper I found that may help -

http://www.bestmaterials.com/PDF_Files/Vent-calculations.pdf

I'm considering doing the roof on our house. The valleys are like most - underlayment, flashing down the valley and a "weave" - one run of shingles crosses the valley, then other coming from the opposite direction overlays the others and gets trimmed just off center of the valley.

Thanks! I just printed it and am going to begin reading it at lunch.

 

[ddawg16]

Hey John,

So yeah, no snow here. This house only has one gable and it is very shallow because there is a vaulted ceiling below. We do have a 3X10 at least every 10. The house does have a lot of ridgeline for venting. I'll talk to the roofer about whether it is adequately vented at the eaves. Right now the attic gets really hot (Like 125-130) on a warm day but that seems to be due to a lack of exit for the heat.

I know currently there are two layers, so we will be removing it all for exactly the reasons you stated. I want to be sure the new roof is done right with all new materials and the structure below is in proper shape. We'll probably sell and move after we retire in 6-8, so I want the house in good shape when that comes. Mechanicals and function come first. If I need to add vents, that's going to get done.

If we need dormers, I can put them on the south side as that sees less wind than the north. We live in the foothills along the south face of the San Gabriels and the Santa Anas can really blow through here at times.

I am going to add some blown-in insulation in the attic at some point. What's there is not in real good shape, but it seems like I am always in the attic adding to the wired part of our network or doing something electrical. I've already added the plastic runners the keep the insulation from blocking the eave vents, so as soon as I think I'm done up there, I'll see about blowing some insulation in.

I always ask my friends at Garage Journal first because I know I'll get some great feedback from people who have done it or are professionals.

Is your roof built using 1x6's? Or plywood sheathing?

If it's 1x6.....plan on putting down plastic anywhere you can....when the tear off the old....your attic will be covered in gravel from the old shingles.

 

[GN4WHLN]

Is your roof built using 1x6's? Or plywood sheathing?

If it's 1x6.....plan on putting down plastic anywhere you can....when the tear off the old....your attic will be covered in gravel from the old shingles.

Uggghhh... 1X6's. I'll have to do the garage too; the roof is the only part not insulated and finished. That is a mess I'd like to avoid. As I think about it, I have things in there that don't react well to contamination.

I can see I'll need to do some prep work. I'll be there the whole time. We are going to do it after I am off for the summer. we're going to decide on the contractor pretty soon though because of the lead time they need.

Thanks man, that's a good tip! IT probably saved me a WTF moment.

-Chris

 

[ddawg16]

Uggghhh... 1X6's. I'll have to do the garage too; the roof is the only part not insulated and finished. That is a mess I'd like to avoid. As I think about it, I have things in there that don't react well to contamination.

I can see I'll need to do some prep work. I'll be there the whole time. We are going to do it after I am off for the summer. we're going to decide on the contractor pretty soon though because of the lead time they need.

Thanks man, that's a good tip! IT probably saved me a WTF moment.

-Chris

Care to guess how I know about it?

After 10 years I'm still cleaning up ****

 

[JasonMcElroy]

I just had a full tear-off roof job about three weeks ago. I'm in NorCal (San Jose).

Radiant OSB sheathing is not required, but a suggested option for hot areas.

Our roofer used "W" metal valleys. It was a ***** to cut the heavy shingles on each side (used architectural 1/4" shingles) but it will last and not accumulate leaves or pine needles as much as a shingled valley would.

Due to the shape of our roof, not having enough linear footage of uninterrupted ride line, ridge venting would not have provided adequate venting. Went with the low profile O'Hagen style vents (eight of them for a 1500sf house).

We did opt for radiant OSB sheathing as we don't have AC. Would like to someday, no money right now.

One thing that is a gold mine in this house is the full house fan. We can turn it on at night and in about 10 minutes the entire house and attic space is full of cool air from outside, with the warm air vented out through the attic space. If we keep the windows and doors shut in they during the summer, the house will stay pretty damned cool.

Jason

p.s. - this was a replacent for a forty year old wood shake roof that was basically turning to dust.

 

[GN4WHLN]

Care to guess how I know about it?

After 10 years I'm still cleaning up ****

That is something I'd like to avoid...

 

[GN4WHLN]

I just had a full tear-off roof job about three weeks ago. I'm in NorCal (San Jose).

Radiant OSB sheathing is not required, but a suggested option for hot areas.

Our roofer used "W" metal valleys. It was a ***** to cut the heavy shingles on each side (used architectural 1/4" shingles) but it will last and not accumulate leaves or pine needles as much as a shingled valley would.

Due to the shape of our roof, not having enough linear footage of uninterrupted ride line, ridge venting would not have provided adequate venting. Went with the low profile O'Hagen style vents (eight of them for a 1500sf house).

We did opt for radiant OSB sheathing as we don't have AC. Would like to someday, no money right now.

One thing that is a gold mine in this house is the full house fan. We can turn it on at night and in about 10 minutes the entire house and attic space is full of cool air from outside, with the warm air vented out through the attic space. If we keep the windows and doors shut in they during the summer, the house will stay pretty damned cool.

Jason

p.s. - this was a replacement for a forty year old wood shake roof that was basically turning to dust.

Sounds like the whole house fan is a really good idea. Those that have them seem to really like them.

 

[sberry]

The snow here plugs ridge vents.

 

[Falcon67]

I sued radiant OSB on the shop and it does make a difference. I'm not sure you could justify the cost of pulling sheathing in good condition to replace with radiant. New construction only adds a few $$. There is about a consistent 20F difference between the under deck temp in the shop and the house (regular OSB) in the summer. Same gray color three tab shingles.

As for venting - our house had a bunch of eve vents but for some reason, no roof vents. When we bought it, one of the first things was to put 5 static 9" round hole vents up there. Spotted the first location, marked it on the outside, cut it with a saber saw and on the last cut the plug blew OUT of the hole by the trapped heat under the deck.

 

[ddawg16]

Gn.....I tried the whole house fan.....I got as good if not better results with the wind powered turbine on the roof.

I have vents on my gables....and that was where I put the whole house vent fan. Problem is, depending on which way the wind was blowing, it was either helping or pushing against.

About the only other option I might consider is a solar powered vent fan that sits on top and pulls air out that way vs pushing it out one of the gable vents.

Next year I plan to redo the wood on the gable vents and will most likely get rid of those vents. I have enough soffit vent to keep it all cool.

I've attached pics of my roof when I did it myself 15 or so years ago....I had a lot of wood damage. I spent a whole week just fixing the damage....and another 3 weeks nailing on the shingles. Every evening after work...2-3 hours of nailing. Next time I'm just writing a check.

As you can see from the pics.....I've made a few 'modifications'....

 

[ard]

OP-

Read up on CA regs for re-roofs:

http://www.energycode.com/?page_id=315

 

[terry603]

I would say do a tear off. people told me to just cover when I did mine 4 years ago.
guess what I found? , the last person that put a roof on did not use any underlayment,none...if I had just covered it over, I never would have fixed the problem I had , the ice dams would have still happened every year.

 

[egdede]

So Cal here! We had a hard time finding a roofer who would put valleys in (make sure they are not nailed in tight).

We went with a metal slate roof, installed by western Roofing Systems. the product is Future Roof: https://www.futureroof.com/steel-roof/slate-roof/

We love it! We plan to own until we pass it on (we're 40 and 50) so the extra 3k over asphalt was well worth it. Our house cools down much quicker at night.

Western Roofing Systems ate it on our job because they normally install other metal shingles which are use bigger panels. They under bid. But, they out it on as bid, and it is nice. My neighbor went with their steel clay tile and it looks very good, much better than cement-clay and, in my opinion, better than the big sheet clay tiles I see on so cal sub divisions.