Room heigth on 1.5

[Berryhill]

Found this site through a search, looks like a place I need to hang out.

If building a 20x30 1.5 story. How much head room can be had? I've looked at attic trusses and have only 7 ft give or take a few inches. I would like at least 8 ft on the 2nd floor and 8ft(9ft better) on the 1st. I also would like a free span for 20×20 area on 1st floor. Will be built on piers.

[Don_P]

Do post framed... pole barn construction.
You can have 8' on the second floor, how wide depends on the framing. If 12/12 rafters sit on the floor you would have around 3' of width at 8'. If the roof is supported by a structural ridgebeam and posts then the roof can lift onto kneewalls. With 2' tall kneewalls the width of ceiling upstairs at 8' tall is around 7' wide. You can keep playing that game up to about 5' tall kneewalls. At that point with 5' kneewalls and a 12/12 pitch and ceiling joists at 8' off the floor the structural ridgebeam and posts go away and the width of ceiling at 8' is 12' wide. Keep playing that game up to 8' tall kneewalls and the full 20' at 8' tall ceiling height.

[Berryhill]

Thanks Don for the reply. With your answer and looking through several build threads, I'm keeping my butt closer to the ground. Just think it would be more than I can handle for a first time.

My original plans are building aa 20×30 pole barn with 10×30 lean to's on both sides. I also like the look of this style. Next question, I am willing to build pole or stick doesn't matter to me. I do want a subfloor rather than concrete slab. I am building in clay and prefer to do all the work I can! Pictured below is a rough floor plan. Which would be better, pole or stick on piers? Roof would be store bought 7 or 8/ 12 pitch. Guess I'm trying to ask what kind of foundation would be best doing it myself if any of that makes sense. I'm located on TN/Al state line.




Snagged this of the web. Style I'm interested in but obviously with shed on the other side and to scale.

[Don_P]

The correct way to build it is with a footing trench, in your area I'm guessing about 18" deep. Concrete is usually poured 16" wide and 8" deep in that trench. Then a block or concrete wall is built on top to a minimum of 8" above final grade. This is a "prescriptive", codebook foundation.

A gravel trench with walls built of treated lumber and treated plywood is another prescriptive foundation.

Then you get to engineered foundations, properly they are checked by an engineer.
A post frame building (pole barn) is one. That is what I'm suggesting. The engineering is well proven

Piers, of the type you are seeing in these build threads, generally are not a good idea. Look at the first two foundations, the perimeter of walls braces the foundation against horizontal loads the building is experiencing, wind or earthquake. A pier has a tough time resisting those loads. A post framed building uses the walls to brace the posts.

Look at the right side of the pic you posted, the rafters run down to the floor. Now look at the loft door, 8' is going to be about 16" above that door where the ceiling at 8' is about 3' wide. As the launch point of the rafters rises, the kneewall, the ceiling at 8' gets wider. The way the roof is built changes as the kneewall height changes. It is simplest if the rafters run to the floor or to kneewalls that are 5' tall or more. There are many ways to get to where you want to go though.

[Berryhill]

How would a man attach a subfloor/ raised floor on a pole barn? What pole spacing?

[Don_P]

Mounting these on the faces of the posts to hold the floor support girders, the girders run between posts then the floor is either built on top of the girders or is flush with them using joist hangers.
http://www.strongtie.com/products/connectors/HUCQ.asp?source=sslumbcat
There are different versions that run on up to about 12,000 lb capacity, with a price that runs with the capacity.

Post spacing and member sizes depends on spans and loads, at 30' long my first try would be with 7.5' post spacing.

[Berryhill]

Don thank you for the replies. I had to sit down for a couple weeks and figure out what I really want. I've had lots on my mind and finally come to a conclusion. It's where I plan to live the rest of my days. I like the country plans but it wasn't the style I want. I want a very rustic look and feel. I found some simple barn plan that I'm going to give it a go. However it turns out, I'll be proud.