roofover/addition questions/thoughts

[ifixbmws]

hi all,
man am i glad i found this place!
ok here is my deal i have a 1985 24x48 dw on block foundation, i have done extensive remodeling now and want to add on to my home we love the property and are happy with the house except for space for our suddenly larger family (we recently adopted 6&7 year old sisters)
my current plan i an 18 ft addition across the length of the house using timber frame construction , i have my own sawmill and can produce rough cut lumber at basically zero cost other than sweat, obviously i will have to change roof pitch and am thinking a pole barn type roofover is the way to go but want to set 6x6 timbers into the existing wall on top of the foundation on the opposite side from the addition to support the roofover is this feasable? we are in a rural area in the southeast and am planning on a corrugated metal roof so the roof will be light but i am a notorious overbuilder , also had considered removing roughly half of the existing roof sytem to vault the ceilings to the new pitch effectively cutting out half of the joining beam along the center of the home what are the structural concerns here?

[JD]

Hi and welcome to the forum,

That is quite and ambitious plan you have. When dealing with changing the structural design of your home, I would really recommend consulting an engineering/architectural company to help you with your plans. This would be for legal and safety issues as well as saving a lot of trips to your local permit office. I would start my planning by looking at the parameters you will have to work within. You mentioned an 18' room. Is this 18' by the length of the home or is 18' the length by 12' or something like that? Your add-on will not be able to cover windows in bedrooms or common rooms, like living rooms. These rooms all need an avenue of egress as well as a percentage requirement on SF of windows per SF of the room. An end bedroom may be alright with windows in the gable end. A middle bedroom could be changed to a hall area to get to the add-on. Point being, there are building codes that your plans need to adhere to.

Professional help will also be invaluable in designing trusses that would work with your design. I doubt that you would want or need to eliminate any part of the marriage beam. You may even need to add to it, depending on the span and design. But professionally designed and manufactured trusses would be the way to go and probably the only way you would be able to get a permit, unless you are or know a structural engineer. Whether you use a scissor or parallel chord truss, the design will have to be engineered approved.

Without giving this a lot of thought or knowing your situation, I would be leaning towards a flat roof of some type for the add-on and a polebarn roof over the whole shooting works, leaving the existing home as it is. This will probably help you a lot at the permit office.

When trying to add a large add-on, it is often easier to design the room as an "L" to the main coach. You will have less problems with window space and room usage. and I think it would be much easier to build.

JMO
JD

[Groo]

could you just build the addition slightly lower, kind of like a split level, to keep the new roof continuous with the original?

I also agree doing the addition off of 1 end might be the better solution. that will also be handy if you ever want to take out the mobile portion and keep the adition. I've seen that method used more than once in this neck of the woods.

don't forget to let that wood dry before you use it. you might even want to have it kiln dried if you are in a hurry.