Can anyone tell me the long term performance differences, pros/cons of Modified Bitumen (MP) vs Dura-Last?
I’m looking to replace a 31 yr old flat roof that currently has asphalt and gravel. The roof is approx. 1250 ft2
MP quote was $7K, Dura-Last was $8K. MP quote would put double membrane near flashing while Dura-Last would put ply over the roof and replace the flashing.
Any comments would be greatly appreciated. Thanks
id say duralast. what are they offering you for warrantees? the duralast should be twice what the modified is.
[quote=“danbosvac”]Can anyone tell me the long term performance differences, pros/cons of Modified Bitumen (MP) vs Dura-Last?
I’m looking to replace a 31 yr old flat roof that currently has asphalt and gravel. The roof is approx. 1250 ft2
MP quote was $7K, Dura-Last was $8K. MP quote would put double membrane near flashing while Dura-Last would put ply over the roof and replace the flashing.
Any comments would be greatly appreciated. Thanks[/quote]
Well, according to Duro-Last, they are “The Worlds Best Roof”. Personally, I find that to be kind of funny, and totally subjectived as are my own opinions. Still, I think it is safe to say the industry would NOT agree with Duro-Last’s self-proclamation of being the best. Although, if MP stands for Mightyplate, I’d recommend you look into using a little more established manufacturer of roofing products.
Anyway, a 2-ply mod. bit. system should be around 290-360 mils thick, whereas the Duro-Last is going to be around 40-50 mils thick. Duro-Last will have heat-welded laps, and if you utilize an APP mod. bit. you can have the laps heat-fused with propane torches.
Personally, if I was going to go Duro-Last, I’d probably look into either TPO or EPDM depending on where you are located. If you want a great PVC, then look into Sarnafil. JMHO
Well, according to Duro-Last, they are “The Worlds Best Roof”. Personally, I find that to be kind of funny, and totally subjectived as are my own opinions. Still, I think it is safe to say the industry would NOT agree with Duro-Last’s self-proclamation of being the best. Although, if MP stands for Mightyplate, I’d recommend you look into using a little more established manufacturer of roofing products.
Anyway, a 2-ply mod. bit. system should be around 290-360 mils thick, whereas the Duro-Last is going to be around 40-50 mils thick. Duro-Last will have heat-welded laps, and if you utilize an APP mod. bit. you can have the laps heat-fused with propane torches.
Personally, if I was going to go Duro-Last, I’d probably look into either TPO or EPDM depending on where you are located. If you want a great PVC, then look into Sarnafil. JMHO
Hi and thanks for your response. The mod.bit is APP. Is there a difference in peformance between heat welded laps (durolast) and heat fused laps (Mod bit.)
?
hi and thanks for your response. the warranties are 15 years for both, no difference
[quote=“Cerberus”]
[quote=“danbosvac”]Can anyone tell me the long term performance differences, pros/cons of Modified Bitumen (MP) vs Dura-Last?
I’m looking to replace a 31 yr old flat roof that currently has asphalt and gravel. The roof is approx. 1250 ft2
MP quote was $7K, Dura-Last was $8K. MP quote would put double membrane near flashing while Dura-Last would put ply over the roof and replace the flashing.
Any comments would be greatly appreciated. Thanks[/quote]
Well, according to Duro-Last, they are “The Worlds Best Roof”. Personally, I find that to be kind of funny, and totally subjectived as are my own opinions. Still, I think it is safe to say the industry would NOT agree with Duro-Last’s self-proclamation of being the best. Although, if MP stands for Mightyplate, I’d recommend you look into using a little more established manufacturer of roofing products.
Anyway, a 2-ply mod. bit. system should be around 290-360 mils thick, whereas the Duro-Last is going to be around 40-50 mils thick. Duro-Last will have heat-welded laps, and if you utilize an APP mod. bit. you can have the laps heat-fused with propane torches.
Personally, if I was going to go Duro-Last, I’d probably look into either TPO or EPDM depending on where you are located. If you want a great PVC, then look into Sarnafil. JMHO[/quote]
Hi and thanks for your response. The mod.bit is APP. Is there a difference in peformance between heat welded laps (durolast) and heat fused laps (Mod bit.)
[quote=“danbosvac”]
hi and thanks for your response. the warranties are 15 years for both, no difference[/quote]
First of all, are you sure you want a manufacturer’s warranty? Depending on what state you live in, the laws of merchantability may cover you; see a lawyer (disclaimer).
Alright, a warranty from a manufacturer is going to come with a minimum charge, and based on the 1250 sq ft you stated you have I suspect you’ll be paying a nice price per sq ft for that warranty.
Why don’t you save that money, use it towards the roof, and ask the contractor to give you a 5-year rather than 2-year contractor’s warranty. After all, the manufacturer is only warrantying manufacturing defects, and then warrants only against leaks caused by manufacturing defects or workmanship after the contractor’s warranty lapses. They do not cover damage by others, metal counterflashings, deterioration, blistering, granule loss, mold growth, structural defects that cause leaks, acts of God, etc. . . .
go with the single ply roof. better than modified if done right.
The heat-welded laps will be stronger than the torched-laps on the mod. bit., but the mod. bit. sheet is a lot stronger and more puncture resistant than the EPDM. If it were my property and I had someone OTHER THAN MYSELF installing the roof, I would NOT go with a single-ply. But then, that is because single-ply roofs are not very forgiving and I don’t trust many people to install them. At least with the robotic welders used on TPO and PVC membranes it takes away the human factor.
The good news for all roofers, however, is that Firestone is coming out with something like a 90 mil TPO which is damn near bullet-proof (gross exaggeration). You install it over a Densdeck or Firestones new HD polyiso board.
[quote=“naas”]Hi Dan
[size=150]www.flatroofdoc.com[/size][/quote]
I have been doing flat roofs for 20 yrs.I prefer Modified Torch down. It is less sensitive to weather conditions during installation and very forgiving when mistakes are made. Modified Bitumen White granular I feel is the best. Maintenance on these materials are relatively easy because most of the times you can use Karnak 81 trowel grade to make most repairs.
However, all roofing materials require a certain skill to install. Most of the times (90%) the problem with a roof is the “installer”. To compare roofing materials is less worry some than looking at the contractor. Most of the time you would be convinced by a salesman and not by the the skills of the contractor.
For me, I prefer Modified Bitumen.
go to my website and see some videos [size=150]www.flatroofdoc.com[/size]
Thanks for your reply Naas.
The mod. bit quote includes scraping existing gravel on roof, repairing any damaged areas, and then flooding surface with hot asphalt. A single layer mod.bit. membrane would be laid throughout with a double membrane layer around the perimeter and flashings.
Is this typical of how things are done with a mod, bit replacement for an existing BUR asphalt/gravel roof?
Please advise. Thanks. I will check out your website
Regards
Dan
no matter what roof ya go with, unless the bur roof is stuck to deck, tear it off.
torchdown is imo one of if not the best roofing materials ever created.
dura last is a little more puncher freindly, but just as good a roof. ive got both roofs 20+ yrs old around me here in tb.
and 7 or 8 thousand.
were are you located danbosvac.
we may have a member close who may be able to help you further.
gweedo.
ha ha funny…ive been roofin for 20 years as well…most epdm roofs i installed were from replacing torchdown roofs …say what you want but i dont like torchdown…and no im not critizing anyone…
I personally would go with GAF TPO. They have multiple colors available, and the product is easy to work with.
Duro-last is over double the cost on the sheet compared to white/gray/tan TPO.
Firestone HD iso is a good product that will take off in the market some day for some applications.
And I’ve been in the roofing business since 1981. I started out working on CTP roofs before moving on to EPDM, PVC, Mod. Bit., hot melts, below-grade waterproofing, etc. Now I get paid to design roof systems for buildings, selecting the best system for each application. So, some roofs get BURs while others might get mod. bits. or TPO’s.
Personally, I like EPDM because it is relatively clean to install and easy to repair, but I’d take a mod. bit. roof over my house any day over an EPDM roof. Also, if I had to have EPDM, I would only trust myself as the applicator as I’ve seen too many poor EPDM roofers. Not to say anybody here isn’t a good EPDM roofer, it is just that I’d have to monitor your work and I might as well just put it on myself if that were the case.
i can argue with cerbeurs …i personally enjoy installing epdm …it gives me a break from shingles every now and then…
Derby Gum torch down 2-ply system verses a roofing system that one can cut the mesh and rip the full length of the membrane hmmm. The contractor has to be certified and licensed to do Duro-last if not the warranty will not be covered also check into all roofing products by Energystar if the material is used that is approved by them then 1 (i.e. homeowner can recieve 30% of cost up to 1500 back on taxes) Check the web site alot of people don’t like torch down cause they don’t know how to do it i did BP refinery in Toledo well over 20 years ago and they are still there go figure Duro-last started as a pool liner system from good ole Saginaw michigan remember also that duro-;ast is a pre cut measured system done in the shop then put together in the field alot of people mess that up
haha I’ve been doing torchon roofs for 25 years and have torn off thousands of squares of failed rubber membranes during that time. 50% of the failures were the seams coming apart and 50% was substrate failure/movement.
I have yet to be asked to tear off a torched down roof.
I don’t like that specification though, “scrape off the stones and torch the new membrane to the old BUR”, there is bound to be moisture in the old BUR, and that will likely cause blisters/bubbles under the new membrane.
They would be better to loose lay then mechanically fix a base sheet over the BUR then torch the cap sheet to that, and get a decent thickness down.
I have seen Durolast on Burger King store roofs here in NZ it looks like crap to me. I have samples they sent me and it doesn’t amke me any more confident either.
Welcome to the site MikeNZ.
yeah jdw its hard to knock torchdown around here.
the best thing to do is say you dont like it because of the fire risk.
its only downfall.
gweedo.
I agree ! Here are just a confirmation of this - http://www.hantekor.com/types-of-roofs/single-ply-membrane/