Uncharted Waters in Flat Roofing?


#1

Hi, I have a boathouse that is recieving a full renovation, and desperately need advice on options for our flat roof/porch. I have not been able to come up with any great solutions because most people I talk to have never dealt with something that is both a roof and a porch at the same time.

The Roof must be

  1. Watertight
  2. able to withstand human traffic and not too hot to relax on (it is also a balcony)
  3. Seamless - there is alot of pineneedle buildup on the roof that likes to find their ways into cracks and rot out any floating roof/grate system
  4. Allow movement/self repair - Because of snow and because the foundation is set in water that freezes, unfortunately the roof is likely to shift when the ice melts
  5. Withstand the sun - there is alot of direct sunlight on the roof
  6. Be appicable in colder temperatures (-5 to +10 celsius)

The previous roof system was tarred with a floating deck to walk on. This system was not great because the pineneedle buildup creates a huge amount of maitenance due to having to lift up the floating deck and sweeping it all out.

That is why I am now looking into seamless systems, such as a rubber membrane underneath with something that withstands traffic ontop… such as the products at www.ecosurfaces.com. or Dek-Master vinyl decking. However I dont think something like this seems great because it requires a heavy application of adhesive… and if the roof shifts I think that this would tear and create holes in the surface

If you have any suggestions I would greatly appreciate it!!!


#2

EPDM covered with walkway pad material or pavers.


#3

roofing.com/gallery/thumbnails.php?album=93

Links to pictures of the boathouse

Thanks RooferJ I will look into that :smiley:


#4

With the walkway pads or pavers (not sure what pavers are)… assuming they are something like 12x12 I am worried that if the boathouse shifts too much that the pads wont want to stay together anymore because there would be an un-level surface causing the pads to pop up


#5

80 mil mechanically attached TPO. Its white, Thick and durable and isn’t glued to the deck. And actually has a higher wind uplift than a adhered roof does.
It comes in 12’ sheets and is welded if you do have any seams.


#6

That place looks like something from “Friday the 13th”. :smiley:

80 mil PVC or TPO


#7

what brand TPO do you use BonaRoofer ?


#8

Strictly Firestone but im biased.


#9

Since you don’t have interior living space beneath the deck, I would go with the EPDM on this project. However, you can NOT use the EPDM as your porch surface, and will have to install a deck system of some sort over top the EPDM. Do NOT consider pavers, as the weight would become and issue, and you would need to really have a structural engineer run some calculations before you could feel good about that choice.

Also, you should know that single-ply membranes like EPDM, TPO and PVC, are all going to be slippery when wet or icy. So, that pretty much eliminates most of them if you are trying to use the membrane as a walk surface. If that is the case, then you are going to have to look at coatings with silica sand cast into the coating for a non-slip surface. However, it should also be noted that joints in plywood/plank roof deck could be a problem unless they are T&G.

I guess if it were me, and I wanted to meet the criteria that I just went back and re-read, I would install a base sheet and at least 3-plies of Type IV felt in asphalt. Let it weather for about a month, and then I’d coat it with a urethane coating with silica sand cast into it for traction. If you don’t like the white color of the urethane, you can always have it tinted at the paint store to a color you prefer.

Let me add, that you are looking for a membrane that withstands foot traffic, freeze/thaw, ultraviolet radiation from solar exposure, and you want the membrane to self-heal, have no application limitations, be seamless, and countless other requirements. Let us all know when you find this membrane, because it sounds like the best of every product rolled into one.


#10

A couple of thoughts…looks like there is already plenty of water in that “room” so why not just put on a wood deck and let it drain thru?
or deck it like a boat? We used to use stuff called arabol on fishing boats, you put it on cloth, it glues the cloth to the wood and waterproofs it, leaving a flexible, textured non skid surface. There are probably more modern versions of the same procedure now days…dave


#11

what about railings?


#12

[quote=“Cerberus”]Since you don’t have interior living space beneath the deck, I would go with the EPDM on this project.

So if it was interior living space epdm wouldn’t work?[/quote]


#13

thanks for all your responses…
just incase you are interested in my situation I thought I would let you know that I have decided to go with a 60 mil vinyl roll produced by ducan, its called dek-master. The roll width is 72 inches so there will be 2 heatwelded seams.
There are similar products to this such as duradek and these products (the thicker versions, not the thin ones such as 31.5 and 45 mil) have been approved by both Canadian and American national building standards as an acceptable roof cover. Duradek has a 10 year warranty, although Im sure they dont last as long as the standard options for flat roofs… however if you come across a client who needs to walk on their roof, this is an option you should definately suggest if they dont mind the extra price!


#14

Not as well as other products when talking about protecting the interior.


#15

Maybe from damage to the roof but from a waterproofing standpoint id put Epdm up against anything you got.
Coal Tar is awesome but only on limited substrates.
Modbits and asphalt are tough as nails but water and sun beat em up.
Pvc resists chemicals but the sun will destroy it.
Tpo is to new to know.
A 90 mil epdm installed correctly with all the details stripped in is imo the best roof going.


#16

[quote=“BornaRoofer”]Maybe from damage to the roof but from a waterproofing standpoint id put Epdm up against anything you got.
Coal Tar is awesome but only on limited substrates.
Modbits and asphalt are tough as nails but water and sun beat em up.
Pvc resists chemicals but the sun will destroy it.
Tpo is to new to know.
A 90 mil epdm installed correctly with all the details stripped in is imo the best roof going.[/quote]

But damage and adhered laps is exactly the problem I have with EPDM. Hey, I’m thinking about building an addition onto my house, and EPDM is a very real possibility. Of course, I would have nobody else put it on but me, since installation is key to a good EPDM roof system. With that said, I wouldn’t recommend it to too many people, since they can’t repair it like I can. Also, I would be using it on a patio addition, not a building. Put a low-sloped roof on my house and there is no way I select EPDM for my house.


#17

I guess that’s why there’s so many alternatives. I myself would put Epdm on my house (if it was flat) and sleep well with the choice.


#18

try not to create a moisture trap were water
lays inbetween the deck and the roof.
this can actually rott out your roof.
as long as your not wearin golf shoes you can use alot of roofs as a deck themselves, ie: torchdown
b.u.r. smooth surface.