Thanks for the response. This may have been the case where the top is hinged. Not sure. Why couldn't I just run 2x6 up to the peak and sister them into the existing 2x6? I've had a few general contractors out that seem to think that would be feasible? No?Be aware that some "modulars" have a two part roof system where the top section is hinged, is stowed in a lower position for transportation, and is raised into final position once the sections are in place on the foundation.
In that case, you would not be moving these collar ties.
I would have to agree. You are modifying a major structural element and will need to get a engineer or the city building department to sign off on your plan, especially because you are dealing with a modular home which was specially engineer to begin with, which means that no one here can give you a "prescriptive" building solution.As to modifying the roof structure, speak with your local building inspector or possibly a structural engineer.
Great feedback. Thank you. I think you've hit it on the head. I think the 2x6 are aligned as a flat roof, which to me is the most ridiculous move made to save a buck, as it puts the headroom close to 6'8 or 6'10" The attic space has a large 28ft laminated beam that pokes out from the center of the floor. I know it's it's to carry the load of the open space on the first floor and it can't be moved. On either side of the attic space are the windows and spots I'd like to make rooms. I'm wondering if I could keep costs down by only reframing the outer third section on either end of the roof, keeping the center space at the current configuration and using that as unfinished storage? It sounds like the only way I'll get more headroom is to reframe the roof. That alone may price is out of the game entirely, but if there was a way to save money by only reframing the space we intend to finish, maybe that's the way to go. As far are your points about insulation and venting, wouldn't a 2x6 afford enough room for insulation while maintaining a vertical vent out the ridge?I don't think it's going to be easy. It looks like the 2x6 part is separate from 2x4 part. If you look at the 2x6 roof as a flat roof - the collar ties are actually flat rafters - and lighter 2x4 pitch added to finish the roof as a gable, then you can't move the collar ties because they are actually rafters. Moving them would mean completely reframing the roof. Maybe the house was built when 6.5 ceiling was legal.
The existing rafters also don't give you enough depth for useful insulation. Even if you use spray foam, ventilation is a must. Check Buildingsciences site for moisture damaged roof deck that was supposed to be draft/moisture proof.
BTW, keep the collar ties and sheetrock above it? Custom steel reinforcement for 2x joint and new collar ties? Maybe possible but these are questions for the engineer. Can the manufacturer answer these for you?
Bud,Hi jl, I've been pondering what could be done with a minimum effort and expense. The double 2x6 at the top of the 2x6 rafters is acting as a header keeping the roof flat and joining all rafters together. That means the collar ties are working in total and not individually. Remove one and that rafter would still be supported by the header. Remember, I'm just thumb buster and not an engineer.
But, if my thinking could hold up under the educated eyes of an engineer, I think you could move the collar ties to above that header, maybe one at a time. Located above it could still be securely attached to the header and it is the header that is supporting all of the rafters. An engineer might give this a blessing at a very reasonable price.
If that were to be approved, then you would still need to decide on how much insulation and if or how to ventilate those rafters. That double 2x6 is right in the way of a clear air path. You might want to read up on an unvented roof assembly. That would allow you to utilize the full space for insulation and get closer to whatever is required for your location.
Bud
