Sunday, January 8, 2012

Shop is done - structurally, needs electrical. Next up - house planning

I don't have photos. Every time I go over there I forget to take my camera. So John's beautiful 30 x 40 shop insulated is built. Chris and Carlton have put gaskets on the doors and they look great. Martin's crew has painted the entire thing. We did pick kind of boring colors though. We'll have to do better on the house.

Duke Power has not run the line to the shop yet. That should happen this week. Don and Buck will install lights and outlets galore. Then the shop should be ready to rock and roll. 

Next - planning for the HOUSE. No one in my family has ever built a house before. We've never been involved in the design phase or anything like that. So it is pretty nerve-wracking and exciting. We're going to go with a kit. I have two main reasons for going with a kit. For one thing, I want to build something. I want to hammer and nail and directly be involved with the construction of John's home. I want it to be something my family has done together. I also think it will be cheaper. 

After hours and hours of perusing the internet, I have decided on a Shelter Kit. It sounds like a quality company and relatively easy to build. I am going to order a 24' x 32' kit with 18" kneewalls this month. They have a 20% off winter special if you pay for the kit by January 31st which I think I can do. Saving about $8,000 on the cost of the kit is worth it to me. Even if we have to order early. We don't have to have the kit delivered until 6-30-12. 

I wish I could work Google's SketchUp program and could diagram the plans for the house. I am so excited. I think it will be incredible. The first floor is open except for a half bath, laundry room, pantry. The kitchen will be probably U-shaped along one wall. There will be 3 doors - main door in the back on the shop side, a door on the front enclosed (kitty) porch and an open porch on the pond side of John's property. John plans to keep his kitties on the front porch so we intend to make that conditioned space. 

Energy Efficiency of the Walls

Now in terms of energy efficiency, this is what I want to do. Upgraded studs to 2 x 6 to be insulated with dense pack cellulose. The R value (resistance to heat flow) is calculated by  5.5" x 3.5/inch since the depth of the stud is 5.5 inches for an R value of 19.25. Now that is not the whole wall R value since the R value of wood is about 1/inch or 5.5. That seriously dilutes the total heat-retaining capacity of the system. That is why we are doing foam "outsulation" or foam boards outside of the sheathing of the building. We will use 2 sheets of polyiso foam - probably 1.5" sheets which have an R value of about 6.5. So 3" x 6.5/inch equals 19.5 for a total R value of 38.75.

Summary of the math calculating R value for the walls:

5.5"cellulose x 3.5 R value/inch = 19.25 

3" polyisocyanuarate foam x 6.5 R value/inch = 19.5

19.25 + 19.5 = 38.5 which should make this a very comfortable house. 

What is code MINIMUM for a wood frame wall in  South Carolina?  R 13. Crazy. The minimum should really be about 19 what you get with a 2 x 6 wall. 

Energy Efficiency of the Roof

Since this is a small house there is no attic. The top floor will have a cathedral ceiling.  

Definition of a cathedral ceiling - A cathedral ceiling has equal sloping sides, meets in the middle of a room at a ridge and also has the same pitch as the (outside) roof structure. 

The manner of insulating the roof will be similar to the way we'll do the walls. 

9.5" cellulose x 3.5 R value/inch = 33.25

4" polyiso foam on top of sheathing x 6.5 R value/inch = 26

33.25 + 26 =59.25

What is code MINIMUM for ceiling R value in South Carolina? R 30. Crazy again.

Why use polyiso foam on top of the sheathing?

It prevents heat from escaping by way of the thermal bridges or the studs in the wall. It is important to use 2 layers of polyiso because you have to cover up the seams on the layer below by staggering the layer above. 

I really should have pictures. This is a seriously word-heavy posting. I just wanted to put some thing up today to let you know what we planning. I'll rework it with photos later. 


  1. Congrats. I can't wait to see how the shop turned out. The house sounds great! When will you be hammering? After I retire? We could bring hammers for a visit?

  2. I plan on getting photos tomorrow. We're going over things with Randy, the contractor in the morning.

    I don't know if John has power yet.