Hey, does anybody know what to do with a built up gravel roof that needs replaced? I have a client that has a roof that is has a minimal pitch (approx 3/12) and they want shingles or metal. I was thinking resheeting, ice and water shield then new shingles but the removal of the gravel to get to a relatively flat surface to overlay with osb has me stumped.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Lighting up an exterior isn't just about ambiance— it's also about code compliance. Here is what the code says about safety and efficiency when it comes to outdoor lighting.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
Fine Home Building
Follow
-
Fine Homebuilding
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial Now -
GBA Prime
Get instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
- Home Group
- Antique Trader
- Arts & Crafts Homes
- Bank Note Reporter
- Cabin Life
- Cuisine at Home
- Fine Gardening
- Fine Woodworking
- Green Building Advisor
- Garden Gate
- Horticulture
- Keep Craft Alive
- Log Home Living
- Military Trader/Vehicles
- Numismatic News
- Numismaster
- Old Cars Weekly
- Old House Journal
- Period Homes
- Popular Woodworking
- Script
- ShopNotes
- Sports Collectors Digest
- Threads
- Timber Home Living
- Traditional Building
- Woodsmith
- World Coin News
- Writer's Digest
Replies
There's not much of any kind of demo work any easier than tearing off a BUR on a residential roof. get a cou-ple square pointed spades and get going early AM when it's cool. You can peel up sections as big as an SUV!
As long as it is at least 3/12, the shingles over I&W is fine.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
I jusr re-read this and see what your quandry is.
you are thinking of removing the gravel only and leaving the asphalt base. That would be extremely hard. what you do is go right down to the deck.
The BUR was applied as follows -
A base sheet that was anywhere from 30# felt to 43# coated base was nailed down to the deck first, with nails about 12" to 18" apart, similar to any dry-in. Probably metal cap nails or roofers with tin-tabs.
Then the two or three plies of 15# perforated felt was hot moppped into place over the baase, then the gravel was sprinkled into hot as it was poured opr mopped on the surface.
more detailed along edges and penetrations but that's the gist of it. To tear off, you just get under to the wood deck and start ripping and prying uyp nails where you encounter them. you will find far fewwer nails than a shingle tear-off, which is why I say it is so easy.
Depending what condition the sheathing is in, you may not need to overlay it with osb. odds are good you will have some minor rot at edges
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
base was nailed down to the deck
Maybe the first layer of felt was hot mopped to the deck, as are a couple I have run into. The sheathing comes up easier than the roofing in that case.
What I did in those cases was first 3000 psi pressure wash to move all the loose gravel and dirt (decomposed needles and leaves), then a good scraping with a flat blade shovel or garden edging tool. Helps to have a whellbarrow on the roof. Layer of selvage roofing over that on a hot day and rolled down to smooth the surface. Then whatever you want on top.
I guess you're just lucky. I all my years, I've never seen that on a residential roof. Specs do allow for strip moped to insulation barrier on commercial sometimes, and I've installed like that, but to mop directly to a plywood sheathing would be asking for leaks ina few years, because of movement in the wood. The rof would pop seams right along the edges of the ply as it moved differently than the asphalt. The whole reson for a nailed base sheet is to allow for a slip sheet.Somebody was trying hard to skip a step on yours and made for extra work for you. It's not common.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I haven't delved into the project enough to see how the tar was applied so I don't know what it will entail but all advice up to this point has been greatly appreciated. It looks like I need to do a little more investigating into the installation method that was used.
Thanks
Best check to make sure your roof isn't coal tar pitch-instead of asphalt.
Skin burns can be severe with "pitch" so best find out first.
I doubt that pitch would have bbeen used on a 3/12 residential. It is preferable for falt roofs. Would probably run right off a 3/12 in the heat of the sun
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Pitch is no more liquid than asphalt once the gravel is on it.In fact it's probably less likely to creep than asphalt.
Ever had a real nice pitch burn?It's something one will never forget and be real careful with the following rips.
Edited 6/5/2006 6:59 am ET by theslateman
Thanks for all the info, it is greatly appreciated. I guess it's game time now. Maybe when I tell them the cost of disposal they will just sell the house and have me build a new one ;)
Piffin led you astray somewhat when he advised against "barring off " the gravel to make a smoother surface for the plywood substrate.
You can get a spud bar or similar to break the gravel loose from the binder and just remove enough so that you can make the plywood work.
That's a whole lot less effort and cost than removing all the plys.
Downside is you don't get to inspect the original roof deck.
Good luck, Walter
We'll have to agree to disagree on those points.
Giving someone a spud bar without knowing his skill level and the roof condition is not a very funny joke. It could be torture. And asphalt is processed in different grades qaccording to the steeepness of the roof it will be used on. Pitch is not. It is comparable in viscosity to the softest dead level asphalt. If used on a 3/12 roof it will be running to the low side in ten years leaving bare spots further up
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I agree that asphalt is graded differently-steep being the one used on that roof pitch.
Coal tar pitch is more solid that flat asphalt whenever I've encountered it.
You didn't answer about the "burn" maybe you haven't come across pitch that often.
Skill isn't tops on the list for barring off-bull strength and akwardness are the two requisites.
the burn didn't seem important. "You didn't answer about the "burn" maybe you haven't come across pitch that often."I've have the crystalization work into the flesh of my inner elbows so deeep it blistered the skin off when i was working a pitch kettle. But I've never had a hot burn from it.I did a pitch tear-off that gave me a fever way up there so I had top spend the night in a cold water bathtub drinking ice cold SevenupI've probably worked with pitch - putting on and taking off about three months of my life. I can recognize the smell at first whiff.
You can tell me whether that's 'often' in your thinking. I know that I don't want to work around it very often though. No smart man does.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That was the point I was making on my first response on this question.
If you start to rip a roof that you don't know is pitch,or don't know the smell of pitch-you could be in for some severe agony due to burning skin or even eye problems from it.I was trying to warn him to check it out for his own safety.
I just wondered if you had ever gotten burned-my first time is something I will never forget.Probably the worst night of my life.
Young and inexperienced-working alone on a small roof on a dormer on a slate roofed house,similar to what the OP was asking about.By the time I realized something was amiss I was already a crispy critter.Like you said the smell of pitch now turns my stomach.
Walter
Ah So,I've had plenty of plain asphalt burns though. nickle and quarter size spots were common enough, but I got careless once and burned all the skin off my right index finger, except5 whjere it was in contact with the next finger over.The healing process was interesting, except for the pain. skin that was thin as Saran Wrap made for interesting anatomy lessons.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
My last house had a tar and gravel roof on a 3:12 pitch. I remodeled and tied into one part of it, and used a long-handled scraper to remove the rocks. The tool has a wooden shovel handle and a thick steel blade about 8" wide at the end.... I mostly use it for scraping concrete form lumber after stripping. Anyway, knocked the rocks off, set them aside for the roofer, and had a very smooth surface for them to start with.
It was sort of like the hard labor they had us doing at Leavenworth when I was there in the 50s, only harder and hotter.
I don't think I would lay plywood over that. The possibility of condensation under the ply or some other unhealthy eventuality would encourage me to just strip it all.
Yep, there are specialy made spud bars that have replaceable blades from two inches to eight inches wide. How hard it is to use one depends on how thick the slag is laid down and how cold the temps are. It is mostly hard labor, but doing it to patcha a leak or tie-in an addition needs more skill than just taking the gravel off for a roof-over. a small leak cna become a large rip withj an unskilled hand driving the spud bar.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I love tools, but I don't suppose I want to buy anything specifically for strippings roofs. That would be a move in the wrong direction at this point... although the general unavailability of young bucks who are willing and able to strip roofs safely means that I do it sometimes.
So is there any way to tell if the roof is pitch or asphalt besides having expierenced both and having had the pleasure of being burnt by it? What burns, contact with the material or is it just the fumes and airborne toxins that are created by a tear off? I think I have plenty of tools that I have used in the past that will get the job done (i.e. square nose shovel, floor scraper etc. ) although it may give me an excuse to make a trip to the lumber yard for a specialty tool just so I can find something else more useful to buy ("Oh while I was picking up the roofing tearoff shovel I found... and just decided I couldn't live without it").
Asubstitute tool would be like an ice chipper.Pitch has a special odor that is hard to describe. scraping it will produce freeborne crystals in the air which are toxic, irritate skin and can cause blindness.It was very rarely used for residential work tho. It is still specified for some commercial and government work
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
First posting here but thought I would add my two cents. As others have said, pitch would not be installed on a 3:12 roof. The softening point is too low and the bitumen would run off the roof on a warm day.
One identifier for coal-tar pitch is to smell it. It smells like creosote, much like the preservatives used on railroad ties or telephone poles. Another technique to identify it is to gather a small sample and immerse it in mineral spirits, (IIRC) pitch will not break down, whereas asphalt will.
Thanks for the tips on how to id pitch, I'm sure I can find mineral spirits in my tool trailer and perform the little expierement. Thanks again!
good description of the smell
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
You da' man.
To the original poster, plan for a major disposal bill on your tearoff. It's easy to get the whole thing off clean, but it weighs as much as a pregnant dinosaur.
that can vaary a lot too.In florida, there were two ply roofs applied on 2/12 pitches with 15# base. That means only 45# of paper and about 90-100# of aasphalt plus maybe 40-50# of gravel. That - if well done - was a fifteen year roof that weighed only 200# per square or less - comp[ared to a 15 year shingle at 240#I never applied less thana three ply on 33# base so weight was comparable to the 240.
But there were five ply roofs that had been resurfaced once with dead level that could run 4-500#/sq.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
tsquared,
A very little bit of poking around at the edge will tell you how it is fastened down. The most common thing is to find the gravel stops rotted in places and the edges loose - and leaking.
Ron
You could install a ridged insallation board over top after removing the gravel but the cost of the board and install is not much different then the removal and disposal. If it was my house I would remove to deck and start new.
Ronbo of All Trade
You can probably sweep a fair amount of the gravel off with a stiff exterior broom. The advantage to this is that you can re-use the gravel if you do another hot tar roof, or you may be able to dispose of the gravel in some fashion that is not as expensive as disposing of the rest of the roofing.
I suggest switching to rubber, like EPDM or TroCal. Much longer life, and no risk of burning the place down.
We had a major hail storm in april and many roofs were totalled. On my block two houses have had the roofs replaced already and two more are getting done today.These are low pitched roofs (2 1/2 X 12 or 3 X 12). These are roofs that were gravel when the homes were built in the 1950's.I've noticed on all the roofs they are not tearing off the roof down to the wood decking. They are leaving the bottom layer which is the tar built up roofing. All of the gravel has been scraped or swept away.I assume these contractors know what they are doing. Maybe it's not necessary to take the roof all the way down to the wood deck.^^^^^^
"The Older We Get, The Better We Were"
"Ha Ha Ha Ha Ha Hah!
;)Certainly it can be done in certain circumstances, but it generally not the best, so I can't assume along with you
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I'm putting a stick framed pitched roof over an existing flat built up roof. I need to make some long cuts perpindicular to the ceiling joist to tie the new rafters into the existing joists.
Whats the best way to make this cut? Obviously, a circular saw will bind up...anyone have any ideas? A sawzall?, chainsaw?