[simiesue]

There is a 2 story home that I am interested in buying in Illinois that has a slate roof (home built in 1990). My first concern is the weight of slate. It has to be much heavier than regular asphalt shingles, right? How does this affect house structure?? Could slate hold up under cold and heavy snow conditions, year after year? What would typical maintenance be for a slate roof? For an asphalt roof, it was easy to just climb a ladder and inspect the shingles, but for slate... it must be slippery to walk on, I am guessing.
Any tips or guidance would be appreciated.

 

[Roofmaster417]

IMO slate is a very solid roof system that has mega longevity.Tinner is a great slate roofer.He checks this forum often.IMO his opinion is worth listening to.

Other great roofers and contractors here at DIY but Tinner is solid with slate roof systems.

 

[tinner666]

There is a 2 story home that I am interested in buying in Illinois that has a slate roof (home built in 1990). My first concern is the weight of slate. It has to be much heavier than regular asphalt shingles, right? How does this affect house structure?? Could slate hold up under cold and heavy snow conditions, year after year? What would typical maintenance be for a slate roof? For an asphalt roof, it was easy to just climb a ladder and inspect the shingles, but for slate... it must be slippery to walk on, I am guessing.
Any tips or guidance would be appreciated.

Slate weigh about 450 pounds per 100 sq. feet. The same as two layers of roof.
Slate will hold up under snow and ice with or without felt. Check out my snowguard page. Most of those pix are of roofs without felt. http://www.albertsroofing.com/SnowGuard Installation.htm

Depending on how hips and ridges were done, they may need to be repointed with roof cement every 3-7 years. You should NEVER walk on slate. It will break them. hink of them like a sheet of glass. I throw them 5 stories to salvage tehm by causing them to land on edge. Drop one 6" 'flat' and it breaks. Inspection if done from the ground with binoculars or from a ladder. Broken ones are fairly easy to see.
NEVER make any repair with roof cement. Slate repairs are charged per slate replaced. One broken slate is just that. One. Cement it, and it will still leak and to repair it will result in replacing 3-5 slates.
A slate roof may only last afew hundred years. Shingles may only last 6-20 years regardless of manufacturer claims.

 

[simiesue]

thanks for replys...
How much does one slate piece cost?? What would a teardown cost? If I understand correctly, slate is nailed in place. If snow sits on the slate for long periods of time, wont water penetrate somehow???
Tinner.. your pix look interesting with the snow guards... what is the purpose though?? Is it to keep the snow evenly dispersed on the roof? Now, I havent seen the house is person (my husband saw it and mentioned the slate roof). Looking at pictures online, the roof pitch is not much. It appears more flat than pitched... is that good/bad?

 

[AGWhitehouse]

the snow guards... what is the purpose though??

Because slate has a smooth surface, snow can easily slide off them when the temperatures are just right. (Just above freezing so there is "slush" along the roof surface). The snow guards keep this unstable snow in place and allows it to melt in place.

Think of a roof like a mountain side. A warming period is like a skier and the avalanche rolls. If you are below it, it's gonna hurt. So the snow guards can literally save lives if the conditions are right.

 

[Windows on Wash]

Pros - longevity, looks, durability, organic materials, clean water run off

Cons - cost, inability to find many good installers any more, proclivity to fail if done improperly (this could go for any of the roofing types but slate requires a more skillful hand).

 

[stuart45]

It appears more flat than pitched... is that good/bad?

Slate roofs are quite common where I live. I've just finished putting one on my extension. They will last a long time if done properly. It is better to have a decent pitch on the roof, but bigger slates with a good headlap can be used a smaller pitch. Nowadays a breather membrane is used underneath as a secondary protection.
Slates vary in quality depending on where they come from. Welsh slate is the best we can get here, but it's really expensive nowadays and cheaper ones from Spain, Brazil or China are often used.

 

[tinner666]

thanks for replys...
How much does one slate piece cost?? What would a teardown cost? If I understand correctly, slate is nailed in place. If snow sits on the slate for long periods of time, wont water penetrate somehow???
Tinner.. your pix look interesting with the snow guards... what is the purpose though?? Is it to keep the snow evenly dispersed on the roof? Now, I havent seen the house is person (my husband saw it and mentioned the slate roof). Looking at pictures online, the roof pitch is not much. It appears more flat than pitched... is that good/bad?

Cost depends on the size, and 'model',ie-Vermont, Munson, Buckingham. Welsh. etc.
Slate repairs can cost from $250.00 for the first and up to $60. or more each. Average cost about $1,000. for the first 'tune-up, then maybe $400.-$600. every several years.

What do you mean by a teardown?? Removal? Heck, lots of shingle guys would be glad to tear the lifetime roof off and give you a 10 year roof. And they'll do slate repairs elsewhere with your trash slate and maybe make another $20K or so.

"If snow sits on the slate for long periods of time, wont water penetrate somehow???" Sure will IF there's a broken one somewhere.

And like WoW said, there are plenty that will nail them on, but very, very few that will install them.

"Looking at pictures online, the roof pitch is not much. It appears more flat than pitched... is that good/bad?[/" More pitch is much better. Lower pitches require even more knowledge, technique, and patience.

 

[simiesue]

Thanks for all the information. I am in Illinois now and just visited the home today. My husband asked for more info on the slate roof - as the listing for the home said that the roof is slate. Well, the home owners had a box with left over samples of the roof material... and guess what.... it truly is not slate. It is like a composite material that is made to look like slate. I read the brochure and it is a naturals composite product with a hail rating of 4 and can supposedly withstand winds up to 200mph. It has a 50 yr. warranty and it has a high fire rating too. You can also walk on the roof without worrying about breaking it. It is rather light weight product therefore not needing the beefed up roof structure that 'real' slate calls for. I have never seen anything like it and our realtor of over 20 years has never seen anything like this either. We also found out the the installer who put the roof on the home back in 1990 is no longer in business.
What are your thoughts now on this product? This product is probably plastic... ???
My concern is that if maintenance was needed on the roof who do you call to fix? Would a roofer with asphalt know what to do with this composite roof? Also, this is the only home in the area that has this type of roof. ugh...

 

[Slyfox]

Not every roofer knows how to deal with slate, real/fake, for every 1 roofer like tinner666 there is 99 that have never installed either.

If I were you I would start looking for a roofer now and create an relationship with him/her by paying them to inspect the roof and give their opinion of it's condition.

There are numerous fake slates on the market today, some have already been time tested and have done well, some not so well and a few more yet that have not been around long enough to be true time tested.

I myself have installed an equal amount of real & fake slate and have seen both the pro's & con's of both and would feel comfortable with "certain" fake slates on the roof of my personal home.

Good Luck.

 

[stuart45]

Most fake slates here are cement fibre. The old ones contained asbestos. Quite light and easy to work with, but the ends tend to curl up in time.