Re-roofing add-ons to Mobile Home


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Old 08-16-18, 08:28 AM
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Re-roofing add-ons to Mobile Home

Before starting these jobs, I thought I'd reach out for some advice, cause apparently, we're just not getting it done right. Hubby & I are DIYer's from 30 years back. We've taken on and completed numerous projects over the years and most have been really good.
However, our backroom add-on is about to be re-roofed for the 4th time and our front porch for a 3rd time. We also need to recoat our Mobile Home rooftop, so our pennies have really got to stretch out and this time will need to last for a very long time, we're both getting up in age & I'm now partially disabled.
Here's what we have...
Both add-ons were attached to the mobile home close to the rooftop, there's a difference of approximately 4" from mobile home and add-ons rooftops. Both add-ons have 2 x 6 rafters,
​​front porch has plywood decking covered with roofing felt and roll roofing, not enclosed on bottom side.
Backroom has OSB covered with roofing felt and roll roofing, we attached flashing under the mobile home rooftop and used caulking and roofer's tar as sealants. We installed insulation directly under the OSB from bottom side than tacked up 1" foamboard to help seal the bottom side.
I've been doing heaps of research, ran across some errors we made during our last installations, so I think I may have our solution however, I find myself rethinking maybe over thinking the whole moneyI checked on various products, most of which seem to be just out of our budget reach.
Both roofs are almost low sloping,
I found the LP OSB TechShield Radiant Barrier, so was thinking about using this for the decking and by using that we can use a thinner insulation, both will save us money.
I checked on the FeltBuster, decided on it, hubby wanted Metal roof, all instruction read to be used with shingles. So I nixed the FeltBuster. My next option was WeatherWatch but all I can find for that is that it's an underlayment. Moved to Liberty Cap paper, it's self- adhesive, can be applied straight to decking, but instruction video show the 3 layer installment.
Questions here,
Can WeatherWatch be used as top layer covering Warrior 30# Felt paper, and if not,
Can we use the Liberty Cap paper with the Warrior 30# Felt paper?
The WeatherWatch is about $30 less per roll, but I don't want to throw away more money
​​​​​just trying to save some money.
I'm on the brink of decision of going down with the OSB Radiant Barrier for decking, 30# felt, next step we've been skipping is applying thin coat of roofer's cement and then rolling out the Mineral roll roofing.
One more question, any suggestions to help with leaking between mobile and add-ons?
​Any opinions or quick responses will be greatly appreciated. Thank you!
 
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Old 08-16-18, 09:22 AM
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I'm not a roofer but I have built additions on several MHs. Ideally you'd have one continuous roof over both the MH and the additions. How flat is the roof? 1/12, 2/12 pitch? any time you have less than a 3/12 pitch shingles or rolled roofing can be problematic. Torch down is best but metal roofing can also work.
 
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Old 08-16-18, 10:45 AM
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You don't put a self adhesive membrane on top of any other form of underlayment... it gets applied directly to the roof sheathing (plywood decking). The instructions should tell you that.

And just an additional comment about low pitched roofs... between 2:12 and 4:12 you need to overlap the underlayment 19", or whatever the mfg recommends. Shingles are fine on pitches as low as 2:12 as long as the low pitch underlayment requirements are followed. You shouldn't use shingles or traditional roll roofing on less than 2:12. And with peel and stick membranes, be sure the product you pick is rated for your slope.

First step should be figuring out your pitch. Put one end of a 4' level on the roof, hold it level, measure down to the roof and see how high the tail end of your level is. A 2:12:roof would be 8". 1:12 would be 4". Just be sure that, depending on which product you use, that you follow any special directions the mfg has for your pitch.
 
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Old 08-16-18, 07:12 PM
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Many thanks for the replies

Both of you have made valid points.
marksr, You're spot on with roof over complete residence, but our budget is no where near $12k for the job. We've checked on metal roof system, roof wrap, self adhesive, and because of low slope, I'm certain shingles would be totally worthless.
We knew we had a leak, but....you know what they have to say about that!!!! 😑😑
I wouldn't be scrambling research now if Hubby's foot hadn't gone through the upper layers
3 days ago. I climbed up there with, blew the rest of the leaves off while he was cutting overhanging limbs, we have several soft spots, so I'm certain the lower half of the complete backroom roof must be torn off and replaced from the 2' x 6's up.
Because of the humidity and excessive moisture we have, we agreed on the OSB TechShield Radiant Barrier for our decking. We discussed that issue again just a few hours ago.
I want so badly to use the self adhesive because my research keeps turning me right back to it. Don't have torch equipment to do heat install, have concerns about even trying it without someone to instruct us as we go. We learn pretty quick, but we failed miserably at researching our options the last couple of times. This time, I kind of shoved my way in and took over the product selection and purchase, because he generally earns the money and I handle our finances. Been that way 32yrs. now, don't see it changing any time soon, at least I pray not.
Anyway, thanks wholeheartedly for your input. Different views can always be helpful in decision making process.
 
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Old 08-16-18, 07:22 PM
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Dont forget ventilation. Roofs can also rot from inside out from an excess of humidity that is trapped inside and can't get out. This becomes even more important if your membrane is also a vapor retardant.
 
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Old 08-16-18, 07:36 PM
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Many thanks for the replies

Xsleeper
Thanks for the helpful tips, I'll go out in the morning and do the level measurement.
Not sure of actual slope, almost certain it's more than 1:12, I'm leaning more towards the 2:12. We had issues with the sloping because of the attachment process.
We had to get close up to mobile home rooftop edge so the roofs wouldn't interfere with the opening/closing of the doors on the mobile home. They open outwards not to the inside, same reason for the sloping, hubby had roof framed to slope more, but when rafters were installed both doors hit on the boards and wouldn't hardly open. We knew it was going to be a tricky build, but we did it anyway. 20/20 hindsight says we should have done the complete roof over from the start. He and I have built several sloped roughs successfully, but were cramped for space on these 2.
He wanted to replace with metal this time but our finances just won't handle right now.
I was almost ready to place the order today, until I started researching a bit deeper, costs just kept piling on until we were so far over our limit that the metal roof got axed.
We've got to replace most of the insulation cause it's saturated and I'm smelling mildew, so we have some cleanup to do as well.
We've had rain everyday for almost 2 weeks now, weather has been sporadic, no telling what time of day it'll rain, so this will be a really tough job, must be done in small sections because of weather and our overall health/age. Can't take those 12-16 hour days anymore.
Again, I appreciate your help and info. If I'm able, once jobs are complete, I'll post update, photos if I'm able.
 
 

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