hello,
wife and i have sold our house we built 3.5 years ago since we (read “she”) wants a different house (ranch this time). So, we are looking at some plans for about a 2,300 ft2 ranch, with a full basement. We are located close to Detroit, MI as an FYI.
We have a pretty good idea of a lot of our figures, however one area we are struggling with is the roof pitch. The plans as drafted suggest a 12:12 roof pitch. We were thinking of reducing to 8:12 to save some money, since there is no bonus rooms, etc.
Our question is, does this save any significant amount of money? If not, the 12;12 pitch appeals to us, but i’m concerned that our framing / roofing costs are going to be quite expensive.
As an FYI, i’m an accountant who really enjoys construction (and my FHB issues!). I really appreciate everyone’s help and comments. I’ll likley be posting some more as we work through this build.
Thanks in advance!
Replies
If you aren't going story and 1/2. I personally wouldn't go above 8/12. My ranch is a story and 1/2. 1952 sq ft on first floor. 700+ sqft on the second floor and its an 8/12.
One thing to think about is getting up there. 8/12 you can still get on it even as an accountant. 12/12 and you most likely aren't getting on that roof which means you are calling somebody out for even the most minor of things.
Do the math
Square the rise and the run, add them together, and take the square root, and you have the length of the roof.
For the 12/12: 12 squared is 144, the rise and run are equal so double it for a total of 288. Then, take the square root of 288, which is 16.97.
For the 8/12: 8 squared is 64, plus 144, for a total of 200. The square root of 200 is 14.42.
Then divide 14.42 by 16.97, for .8498. So you would use 85% of the materials to roof the same area at an 8/12 pitch that you would for a 12/12 pitch.
The trusses shouldn't be that much more expensive. But depending on the material choices, 15% of the sheathing, underlayment and roofing cost could add up.
I would ask for proposals at both pitches with similar materials and make the choice before hiring the contractors. I would probably include an option to upgrade the materials, on the lower pitch roof, to include more ice an water sheild, and possibly better shingles.
If I were doing the work myself, I'd probably go with the lower pitch just because I like working on an 8/12 roof better than a 12/12 roof.
I personally don't see the point in going over 4/12 unless you live in heavy snow country or are going to take advantage of the attic.
I was thinking th same thing. If you aren't using the space up there, then use the lowest slope you can get away with but there are design issues. A taller roof makes a home seem larger than it is but its an expense for complete asthetics only...but then so is every dollar spent on landscaping.
as a side note, its really interesting to see the differences in regions. Every roof issue on here someone assumes trusses but in our area trusses are the exception. Nearly all custom homes are stick built roofs around here.
Around here you can measure how pretentious a house is by the roof pitch. The vast majority are 4/12, some up-scale ones go to 6/12, and McMansions go 12/12 or even steeper. But of course, we're not that far from Lake Wobegon.
Hardly makes sense to build a high pitched roof if you aren't utilizing the space. Most ranches are low slope, 5/12 is common, 4/12 looks like a trailer, 6/12 adds some interest. Rafter length on a 12/12 pitch is 16.97 inches per foot of house width, 6/12 is 13.4. A higher pitch will cost more for framing, trim, sheathing, roofing and labor. Labor adds up since a 12/12 will have to be staged all the way. You won't save 50% going from 12/12 to 6/12 but you will save some and those savings will extend when the roof has to be redone in the future. Architecturally, the look is quite different. That aspect has to be considered.
A 12/12 roof will have an odd appearance. The right angle on a roof looks wrong in general. A ranch does not normally have a steep roof, so it would look doubly odd. Go for the 4/12 or similar, I think you'll be making a mistake with a steep roof on a ranch. My cape has about a 4/5 pitch, and it's pretty steep, but it would not look like a cape with a low pitch. A ranch would not look right with a high pitch.
since you are in Michigan.. a 12/12 pitch is not unusual.....so the framers and roofers are not going to be overly concerned.
you like the appearance of the 12/12.... so..... go for it..
a good compromise and similar appearance is 10/12... lot's of Capes are built 10/12....
the difference between 8/12 and 12/12
a 2300 sf ranch is an awfully large footprint..... is it one story or two... is the 2300 the footprint ?
if so... say the width is 36' .. then your long dimension is 64' ????
is this an L...... or T ...... ?
if you have access to a CAD program and can develop your plans on 3CAD , you can easily change the roof pitches and rotate the design in 3D ... see how the 8/12 , 10/12 and 12/12 compare
those programs will also give you roof material lists and you can compare different scenarios
but ... the difference in cost would not dissuade me...... the appearance would be very important... this is not a starter home
just for comparison:if your ranch is 36x64 , an 8/12 pitch roof would have about 3150 sf, a 10/12 would have about 3450 sf ( 300 sf more ), and a 12/12 would have about 3750 ( 600 sf more than the 8/12 ).
When I did trusses design for a living, this was one thing we did a lot of. (Trying to cut costs)
Going from 12/12 to 8/12 should save a lot of money. The trusses would definitely be cheaper. If they're more than roughly 13' tall they'll have to be built in 2 pieces (Piggy back trusses) for shipping reasons. That adds a lot of money in trusses and labor. Dropping to 8/12 or so would probably eliminate that.
Sometimes people would ask us to reduce the pitch to the point that piggyback trusses were no longer needed. Sometimes that was an odd number, like 7.8 or 8.2/12. But with computerized design it's no big deal.
You'd also save money on plywood, underlayment, shingles, siding, etc. by lowering the pitch.
Ya might want to talk to your GC about this. They might have specific recommendations that would make more sense than we could, since we haven't seen your plans.
Amazing how one's occupation changes ones' perspective.
I've never framed or built a roof ... but I've walked on plenty, and I've belly-crawled plenty of attics. While a bit off topic, let me describe my idea of the 'perfect' roof.
For me, the outside of the roof would be a 'mansard' or barn roof shape. The outer, more vertical part would be at a pitch slightly steeper than the angle you're supposed to set your ladder at; set your ladder once, and you can work the whole section.
The upper, or more horizontal section would be at a shallow enough pitch that you were comfortable walking on it.
On the inside, the clear height (between rafter and joist) would never be less than 2 ft. The roof would extend over the eaves enough that a man inside the attic has clear access to the tops of the outside walls.
Truss design would give you a clear paqth, at least three foot wide and two foot tall, right down the middle, at a right angle to the trusses. This path would be completely covered with plywood at least 5/8" thick.
Remember: the initial construction expense of a building is but a small part of the total, lifetime expense. "Cost accounting" is much more complex when you're building something you plan to use, and are not able to pass on the consequences of your 'savings' to the next victim.
You really need to keep in mind that attics are far from 'wasted' space; all the ducts, circuits, and pipes that pass through them will need servicing sooner or later.
Remember: the initial construction expense of a building is but a small part of the total, lifetime expense. "Cost accounting" is much more complex when you're building something you plan to use, and are not able to pass on the consequences of your 'savings' to the next victim.
Ah, but no one does that cost accounting. The builder doesn't care what the maintenance costs will be, and the potential HO is just interested in the best "value" for his $$ (meaning granite counters, SS appliances, etc).