Flat roof covering

[Lonicera]

Because this will be my first effort, and I have little construction experience, I want to start with a flat roof.  If anyone has done one, what sort of covering has been most successful for you?

For me, it's more than the simplicity of the flat roof,  it will be a good way to gain elevation, to view any critters who've strayed from the home base.

Thank you for any suggestions.

[peg_688]

Flat roof's always leak , even the ones done by pro's . There are many ways to do it , torch down , walkable roof/ deck  ,  membranes , 90 LBS. roll roofing (most common for DIYer) .

I highly recomned a shed style roof with some , even a little pitch,  as little as 2 in 12 will greatly reduce the roof leak potential.

[Lonicera]

Flat roof's always leak , even the ones done by pro's . There are many ways to do it , torch down , walkable roof/ deck  ,  membranes , 90 LBS. roll roofing (most common for DIYer) .

I highly recomned a shed style roof with some , even a little pitch,  as little as 2 in 12 will greatly reduce the roof leak potential.



That's what I thought, but if I use what you suggest, on a shed roof,  can I still walk on it?

[peg_688]

It depends on what type roofing you pick.

A common old roll roofing 90 lbs will put up with some limited foot traffic , think maintance , IE clean gutters, cut of a odd overhanging limb , but not general everyday live on it like a deck would get.

Torch down , which should be applied by a pro , lots of odd tools , heavy , need to be shown how to install , etc issues . Along with burning down the house with the torch   issues .   Would also not be good for daily foot traffic .

The walkable deck menbranes are made for that , goggle those , again MTL will need a pro to install it properly. Again lots of little stuff involved.

Then there's is deck  guard railings , proper flashing at same , so how bad do you want to walk on that roof  

[youngins]

Where in TX are you?

[Lonicera]

Where in TX are you?

San Augustine

[youngins]

My neighbor in Colorado built a structure with a shed roof:

http://web.mac.com/leland1234/iWeb/Hermitage/Shed%20Photos.html

[glenn-k]

How big are you talking?

City or country?

Will you have direct walking access to the roof or climb a stairs?

Is it a new structure or addition?

[Lonicera]

How big are you talking?

City or country?

Will you have direct walking access to the roof or climb a stairs?

Is it a new structure or addition?

Way out in the boonies, and it will be used for storage or a garden shed, later on.  I wanted something very simple, which would give me skill and confidence to do the main cabin, later on.

Talked to the county judge, and no building requirements, nor do I think anyone cares.  Not that I want to construct something shoddy, which would present a danger.  I even considered sheet vinyl--because this is not a forever dwelling.  

Probably a simple staircase to access the roof.

A friend has a garden room, attached to her home, and I'm guessing it's 10x20, so something like that, or at most 12x24

[glenn-k]

OK - How about an EPDM pond liner or similar, let it lap the sides a bit - put treated 2x flat around the perimeter spaced up a 1/4 inch or so - well sealed at penetrations with mastic, then about 1 1/2 inches of sandy loam on top with succulents growing on it - safe code type guard rails all around.  

An idea I picked up from Ken Kern.  He actually used roll roofing but had a slight slope on his shop roof.

Roof members would have to be beefed up a bit to support this slight added weight.

[Lonicera]

OK - How about an EPDM pond liner or similar, let it lap the sides a bit - put treated 2x flat around the perimeter spaced up a 1/4 inch or so - well sealed at penetrations with mastic, then about 1 1/2 inches of sandy loam on top with succulents growing on it - safe code type guard rails all around.  

An idea I picked up from Ken Kern.  He actually used roll roofing but had a slight slope on his shop roof.

Roof members would have to be beefed up a bit to support this slight added weight.

In The Little House Plan, the 14x24 states 2x10.  How much beef do I need to add?

Moreover, and not to skimp on the beef, a soiless mix (Pro-Mix, Sunshine, etc.) is less weight, with the peat moss as the base, and the addition of vermiculite and perlite, to retain moisture.  Of course it's more expensive, but I think the cost is offset by the additional R value it would add, by increasing the depth of the "soil"  to 5 or 6 inches.

I was considering using grass on this mixture, then tossing a few of my geese on the roof, from time to time, to mow and fertilize.

[glenn-k]

Soil generally runs about 100 lbs per cu. ft.  A light weight mix would run less than that with good drainage.  Water runs about 64 lbs per cu ft.

Nothing official - I'm not an engineer- just a guess but I would go to 2x12's and double them as you are about adding the normal allowed live load as a dead load.

You could keep all penetrations of the membrane over the side if you attach your guardrails to the extended ends of the joists and the end trim member.  Be sure to drop your trim board on the high side a bit to keep water from following the roof joists down slope into the house.  This will make a drip edge.

[Amanda_931]

Or plant a living roof like Glen's done.  His vegetable garden--or part of it--is up there.

Needs to be heavier yet because of all the soil.  Rob Roy's books mostly have a section on them--his sauna book gives specifics, IIRC, for a smallish building.  I'm sure there are other good links around now.  Or Tony Wrench's Round House--although his way of building ended up with a stout house for him, it might yield the balsa wood house some friends have in a comic strip posted at their house.  Even most of the living roofs have got a bit of slope on them.  As in, you don't want a pond, you want drainage for your garden.  3 in 12 slope (three inches up for every foot across flatways) is eminently walkable.  Seems like I've even sat on them a time or two--preferably not with black roll roofing in the daytime!  But it might not be loungable

Living roofs are now mandated in some cities to help get away from the urban heat sink.

I think I'd rather do rainwater collection, so I haven't studied up on them much.

There are paint-on rubber roofs,  Some of the old ones Alex Wade (an architect who was active in the 70's) liked very much.

There must be 7 or 8 systems out there.  Here are a couple.  No experience with any of them (although some do stress their green-ness, and their usefulness for rainwater harvesting situations):

http://www.acrylabs.com/Roofing_Systems_Products.shtml

http://www.epdmcoatings.com/  (looks like it's mostly for leaks, although one of their products seems to be more-or-less usable as  :)the roof over plywood)

http://www.conservationtechnology.com/ general info on their green roofs, which all seem to be very low slope.

http://www.acrylabs.com/Roofing_Systems_Products.shtml

[glenn-k]

Here is a picture Lonicera was trying to post.

Should be an easy one with the Little House Plans  I think John would recommend some bracing panels in the front in place of some of the glass on that design.  Just a guess.  Maybe there is some at the far end behind the tree - the one section appears to be a door.