I need advice about roofs

Posted by: u6213129461734706 on 27 October 2010

I bought a nice old house about a year ago. The inspection report said it would need a new roof at some point. The roof is flat, highest in the middle and gradually slopes down to both the front and back. It's what you call a built up roof, or BUR, asphalt was heated in a kettle, pumped up to the roof, swabbed across the roof deck with a mop, then a layer of felt, repeat several times and end with a final coat of asphalt topped with small sized gravel. I had a small leak fixed 2 months ago, using the more modern method of material that is unrolled and a torch applied to bond it to the roof.
-The thing about flat roofs is that you don't know there are cracks until you see your ceilings becoming wet and damaged. I can't work now because of my OCD (I'm on disability) so I have time to work on it myself. I've done my own repairs by hauling solid asphalt up to the roof and melting it with a torch and pouring it over the area, then moving the gravel back in place. Works great. I met many people in the industry, and did extensive research, to see if I could re-do the whole roof by myself, basically by "cleaning" down into the top layer, refreshing the felts with an asphaltic primer, then applying a thicker mass of fibered liquid asphalt or melting solid asphalt and pouring it. After doing a test section, I came to several conclusions:
1) There's far too much organic material on the roof - mixed in with the gravel is black soil, which comes from leaves and other organic matter breaking down (almost 30 walnut trees, trimmed them back this year-but previous owners let leaves collect, moss was allowed to grow, etc). Moving gravel aside is one thing, but all this dirt stays damp, has to be dried out, hard to clean the top surface properly to get down to clean asphalt, so that the asphalt primer will bond well. Takes forever and a day to clean.
2) Did a test cut into the roof, down to the wood decking, the roof was saturated with water between the top layer and deck, at least in that area. Re-sealing the roof would mean trapping water in it, wherever water has saturated the built up material.
3) You can't tell by looking what areas might be cracking and accepting water, etc.
-So common sense prevailed, I'm going to have it re-done from the deck up by a professional. Considering 2 leaks so far, and the cut test, the roof is telling me it is aged and due for repair, and trying to save a buck by doing it myself would be a mistake. The best company here in Ontario, with the best reputation and excellent referrals, is a company I trust completely, and they want almost $40,000 Canadian, with tax to do the job. There are two or three others, who I know I can trust, and their estimates are lower, but not far off the mark. Needless to say, no upgrades to my Naim system for some time. My wife and I got the bank to re-do our mortgage to include almost $35,000 to direct towards the repair, and we'll have to find another way to finance the balance.
-I'll cut to the chase. This house was purchased a year ago, at such a fantastic price that I don't mind this cost (just sooner than I expected). I would like to know what other forum members know about replacing flat roofs and their experiences. Has anyone been able to rebuild the roof with much more slope to allow the roof to be shingled instead? Did it cost much more? Can a flat roof take the added weight of more structure, safely? I'll probably just do another built up roof again, and take the 10 year warranty, and be done with it. I should have done more research before buying a house with a flat roof. My bad. I won't do anything stupid like just add a new layer overtop-it's cheaper, but has problems with airlocks, bubbles, and horror stories abound about leaks starting just a few years down the road. It's a much more difficult type of roof to get "right" as opposed to shingles. My wife and I need it to last for ten years, at which point we'll have to do it again. It's such a huge investment I'd really appreciate hearing what others have to say about flat roofs.

Thank you,

Dave
Posted on: 27 October 2010 by Steve2701
Dave,
That must be a huge roof for $45,000! There are several options here in the UK now that give a 100% coverage in a single piece for BUR, which I must admit I am looking at. I did my own 22 years ago & it is just starting to fail at the edge points, so it will need re doing in the next 18 months or so - depends on how severe this winter is. To make a flat roof up to accept shingles will need (I think) a minimum of 45 degree pitch, and even then the shingles need at least a 50% overlap. As you say, an engineers report would be wise to check if the structure would take the additional weight.
Getting the roof right is a major point, and while your at it - it is probably worth massively upgrading the insulation in the joist area - 4" or 6" FRK rockwool would probably save you a lot of heating / cooling costs over a 10 year period (my guess is that there is probably very little there at the moment?)
Worth a thought.
Good luck.
Posted on: 27 October 2010 by BigH47
Hawk are there any local architects/builders that do renovation/extensions that you could speak to vis a vis any alternative roof designs or modifications? As Steve was saying the obvious being a steeper pitch and shingles/tiles, but weight might well be a problem.
Tiles never seem to be mentioned as an option in N America though.
Posted on: 27 October 2010 by Derek Wright
Have you considered using zinc as a covering material? The edges are crimped together - it can look very nice.
Posted on: 27 October 2010 by roo
Try and find an installer that does EPDM rubber roofing. It lasts a lot longer than a tar and felt roof and it a piece of cake to install as you just fix it with an adhesive. Quite a few places here offer an insurance backed 20 year warranty on their installs and EPDM is supposed to last much longer than that. I think the Honda factory in the UK has an EPDM roof. The cost has also come down a lot recently so you may find it OK cost wise.

Roo
Posted on: 27 October 2010 by u6213129461734706
Thanks so much for the responses. The house is about 3500 square feet.
-The roofer wants between $3,000 to $10,000 to add insulation above the deck and below the BUR. I have a choice in that price range from one inch to three inches of insulation. Maybe opening the decking and upgrading the insulation between the rafters would be a better choice.
-The rubber roofing sounds interesting, and I think it comes in white or silver to reflect the heat. Heating is very reasonable in Canada, cost-wise, using gas. But cooling in the summer is becoming a very expensive proposition due to the cost of hydro. Plus, my air-conditioner is ancient and will need to be changed eventually.
-owning an older house does bring a lot of added expenses.
-As per the advice, I will try to get more info about changing the pitch of the roof if possible, then going with shingles.
-I appreciate all the comments. Steve, getting 22 years out of your roof is most impressive. Are you a tradesman or just handy? what weather conditions do you face? I assume you are in the UK.

Cheers!

Dave
Posted on: 27 October 2010 by Haim Ronen
Hawk,

I had a flat EPDM rubber roof for twenty years. The material flaked and had to be recoated every few years for protection from the sun. A TPO (newly developed material) roof is superior for holding water and lasting for a long time on top of never needing any coating:

http://www.specjm.com/commerci...oofing/tposingle.asp

Had one installed two years ago and can highly recommend it.

Haim
Posted on: 27 October 2010 by u6213129461734706
Haim, thanks for the info, I checked out some companies online here in T.O. and will get estimates. The difficulty will be in finding an installer here that I can trust.

Dave
Posted on: 27 October 2010 by Haim Ronen
quote:
Originally posted by The Hawk:
Haim, thanks for the info, I checked out some companies online here in T.O. and will get estimates. The difficulty will be in finding an installer here that I can trust.

Dave


Dave,

The key is to find someone with good reputation that has been in the business for a while. The company which installed our TPO roof is the same one which did the PDM roof of our house in 1989. TPO is mainly used for commercial structures and most of those installers have a lot of experience and are likely to be around when needed. We received from the company we used a 10 years full maintenance warranty.

If you are interested, e-mail me (hronen@comcast.net) and I will send you a picture of our TPO roof.

Good luck,

Haim
Posted on: 30 October 2010 by northpole
Suggest you have a read through this website:

http://www.sarnafilroofassured.co.uk/index.html

Sarnafil is one of the better known products whose manufacturer provide insurance backed guarantees.

One of the reasons they can offer the guarantees is not just the quality of their products, but as Haim has just hightlighted, the quality of the people used to install their product. They also inspect the works themselves before signing off the warranty.

The devil really is in the detail and I imagine it would be difficult for a single residential re-roofing project to be able to establish confidence in the folks turning up to work on your home.

Hope this is of some help.

Peter
Posted on: 30 October 2010 by u6213129461734706
Peter, the top company here who I trust and know to be trustworthy and who tend to be the most expensive, they shocked me by saying that they don't do EPDM and they don't do TPO. So with them I'm stuck with 2-ply. I have to check the other companies out, and most of them do PDM and TPO. I will check out the link you sent and I thank you.

Dave
Posted on: 31 October 2010 by Julian H
Dave

Consider a green roof. Check your roof structure is up to the added weight first though. A Green roof may initially cost more but it should last a lot longer and be well insulated [both thermally and acoustically].

Julian