EPDM roof vent

[Brandon Whitmore]

Is there a proper way to install a standard roof vent on a EPDM roof? I checked a couple of sites and couldn't find anything showing a roof vent detail.

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This is my first ever EPDM roof-- they just don't use them much around here. It has been installed on a 1980 mobile home, and was installed over the existing domed style metal roof

[BornaRoofer]

Those type of vents are for a sloped roof they have a good chance of leaking even if they were properly flashed in.

On a flat roof a curb would be installed or a stack and the proper vent would be placed on that. There is also a one way vent made just for flat roofs that's about 8" high with a little mushroom cap.

Flat roofs normally are not vented the way a residential roof would be unless venting out moisture from an old roof left in place.

All that being said 5" epdm form flashing and primer around the flange would probably seal it up. That is until snow builds up over it or the metal joints inside the can leak.

[kurt]

That isn't it. It may not leak now, but it will.

You need a one way breather vent.

[Brandon Whitmore]

Thanks guy's .......I pretty much knew that wasn't the right way, I just wanted to know what the right way was. These vents are actually being used as the bathroom exhaust openings.

Which brings me to another question......... Did they originally provide attic ventilation for these older mobile homes with the domed roof's?

[Bill Kibbel]

Breather vent:

One per 1000 sq. ft.

Did they originally provide attic ventilation for these older mobile homes with the domed roof's?

I didn't know that any mobile homes had attics.

[kurt]

I've never seen a mobile home. I have no idea how they should be vented.

Do they have attics?

[Brandon Whitmore]

I didn't know that any mobile homes had attics.

Not accessible ones, but newer manufactured homes have ventilation provided. Maybe instead of saying attic, I should have said air space between the roof and ceiling?

Bill, thanks for the breather vent pic, I am yet to see one of those on an inspection. I only see a flat roof system once every few months at the most.

I almost turned down this mobile home inspection, but things aaaarreee sllllllooowwwww right now. The place was selling for about 20k furnished. I am guessing that most people purchasing these things opt to not have them inspected.

[Tom Raymond]

Originally posted by kurt

I've never seen a mobile home.

Really?

Lucky Bastard![]

Tom

[hausdok]

Originally posted by Brandon Whitmore

The place was selling for about 20k furnished. I am guessing that most people purchasing these things opt to not have them inspected.

Most of them I see are about 150K and up. I imagine people buying them in that range will get an inspection. It's possible to get them cheaper - I've think I've seen a few advertised for under $40K - but those are probably not worth the effort.

My mother bought one in Florida a couple of years ago for about $44K. It's actually in pretty good shape and probably would have brought about $160K around here.

ONE TEAM - ONE FIGHT!!!

Mike

[msteger]

I see a dozen or so mobile and manufactured homes per year, but I've never seen one with a flat roof or EPDM (or other membrane, for that matter) installed. All have had asphalt shingles installed. None have had attics either, but simply 'cathedral' ceilings with minimal ventilation from soffit to ridge b/w ceiling and sheathing. Many of the mobile and manufactured homes I run across also have very short plumbing stack vents.. we're talking about 3~5" high that I call out all of the time.

[Tom Raymond]

Matthew,

The low slopes and short stacks are to meet DOT regs, remember these things are pulled onto their lots with wheels under them. The cambered roof in the original post was very common on older units and are usually constructed of simple trusses (2x2 top and bottom chords with scrap paneling for gussets) that are rarely more than 6" from ceilling to roof and typically 24" on center. The EPDM must be a cold process, the heat required to bond a hot process distorts the metal roof deck something fierce.

Tom

[msteger]

Forgive me, but I don't understand your point, Tom. Are you saying that stack vents on a mobile home don't need to be the normal ~12" high?

[hausdok]

Originally posted by msteger

Forgive me, but I don't understand your point, Tom. Are you saying that stack vents on a mobile home don't need to be the normal ~12" high?

Well, Duh

They are regulated by the FHA code for manufactured homes and can't be less than 2-inches above the roof.

ONE TEAM - ONE FIGHT!!!

Mike

[Brandon Whitmore]

Forgive me, but I don't understand your point, Tom. Are you saying that stack vents on a mobile home don't need to be the normal ~12" high?

In Oregon, vent pipes only have to be 6" high. Is the 12" height a state requirement, or model building code requirement in your area?

We have a manufactured home building code in this state, but I have never read it to find out if the 6" requirement exists. (I just write them up anyway's-- it is pretty simple to extend a vent pipe)

[Bill Kibbel]

Around here in IRC land, they're supposed to be 6" above the roof or 6" above the anticipated snow level, whichever is greater. On new homes, most are between 5"-8". I don't think the municipal inspectors pay much attention to them.

We once had 28" of snow, so I guess they should all be 34".

[kurt]

Don'tcha love it when they talk about "make it higher than the anticipated snow load"?

There isn't any such thing.

[Brandon Whitmore]

So, what's a snow load? In my inspection area we had better watch out, we may get a couple inches of build up for a couple of day's.

[Tom Raymond]

Originally posted by msteger

Forgive me, but I don't understand your point, Tom. Are you saying that stack vents on a mobile home don't need to be the normal ~12" high?

My point is, and Mike O got it, that it is manufactured and so is subject to different standards than conventional buildings. If you are going to inspect manufactured housing it would be a good idea to familiarize yourself with those standards. Most of the codes we are familiar with simply don't apply.

Case in point, about 15 (maybe more) years ago there was a double wide placed on a permanent foundation on a building lot here. The AHJ would not grant a C of O because the double wide had plastic supply plumbing that was not allowed (by code) in new construction at the time. The Manufacturer would not replace the plumbing because it was allowable for manufactured housing. I have no idea what the outcome was, but the building was empty for over a year until a solution was found.

Personally, I think the different standards are a huge disservice to the people who choose to live in/own manufactured housing, as well as the professionals that have to deal with them, and that they (the buildings, not the occupannts[]) should be held to the same minimum standards as any other housing unit.

Tom

[Jim Katen]

Originally posted by Tom Raymond

. . . Personally, I think the different standards are a huge disservice to the people who choose to live in/own manufactured housing, as well as the professionals that have to deal with them, and that they (the buildings, not the occupannts[]) should be held to the same minimum standards as any other housing unit.

Tom

The different standard allows for a level of affordability that you couldn't otherwise achieve. This allows a significant segment of the population to afford housing that's safe & healthy if not particularly durable.

- Jim Katen, Oregon