Slab heating with high ceiling

[Steve from Socal]

I am trying to get a sense of what I need and about what it would cost to put in floor heat in a building.

The location is Hutchinson Kansas, the building is 6000 sq ft steel frame with brick walls on two sides and steel panels on the other. The building is 60 X 100 and is oriented with the gables north and south. The brick walls are the north and east walls. The building will be 18-19 feet at the eaves with 3-12 pitch open ceiling. The walls will have R-19 and the roof will have R-19 or better.

The floor will have to be thick enough to support a forklift with at least 1000 per inch of tread load. The floor will also have 12 foundations for the steel frame and bridge crane. The floor will also be poured inside an existing stem wall. The building is open on the south and west sides, it abuts other building to the north and east.

The building will be in use daily and a shirt sleeve environment is the goal.

What effects do the foam insulation have on the slab with regards to weight bearing? The slab will require a fair bit of steel, will the foam require additional steel? Is slab heat going to be able to do the bulk of heating or will the slab heat be marginal due to ceiling height?

The project will start in early April, I could use some good info on this application.

Steve

 

[walrus]

I am trying to get a sense of what I need and about what it would cost to put in floor heat in a building.

The location is Hutchinson Kansas, the building is 6000 sq ft steel frame with brick walls on two sides and steel panels on the other. The building is 60 X 100 and is oriented with the gables north and south. The brick walls are the north and east walls. The building will be 18-19 feet at the eaves with 3-12 pitch open ceiling. The walls will have R-19 and the roof will have R-19 or better.

The floor will have to be thick enough to support a forklift with at least 1000 per inch of tread load. The floor will also have 12 foundations for the steel frame and bridge crane. The floor will also be poured inside an existing stem wall. The building is open on the south and west sides, it abuts other building to the north and east.

The building will be in use daily and a shirt sleeve environment is the goal.

What effects do the foam insulation have on the slab with regards to weight bearing? The slab will require a fair bit of steel, will the foam require additional steel? Is slab heat going to be able to do the bulk of heating or will the slab heat be marginal due to ceiling height?

The project will start in early April, I could use some good info on this application.

Steve

If you're going to use radiant, you want insulation under slab or you are going to have nice toasty gravel under the slab. Radiant will heat the space no problem. Are you sure on the tread load? 1000psi seems high but what do I know Might want an engineer to get involved?

 

[Steve from Socal]

The tread load is based on the wheel weight of my 24K forklift using published axle weight loaded. The actual PSI is a bit higher than the figure quoted. I have an architect and structural engineer involved. The engineer seems to not quite grasp that this is not a Fortune 500 build! I may enlist the engineering at the steel building company to develop the foundation plan.

Having said that, I still want to know the impact of the factors mentioned on the slab and how effective the radiant heat alone would be in the building?

Steve

 

[Highbeam]

The only thing you have to worry about is your foam being weaker than the underlying soil, the reinforced concrete will do the job of distributing the load to the subgrade.

2000 psf is pretty weak soil. 2000 psf = 13.89 psi. You can use regular 15 psi foam, this can be extruded or expanded.

3600 psf soil is very strong soil. 3600 psf = 25 psi and is the standard rating for extruded foam.

Yes, you want foam under your slab. It can be white expanded or pink/blue extruded, both work fine and both are available in different psi strengths.

 

[BadgerBoilerMN]

Radiant floor heating is perfect for garages or shops with high ceilings. The radiant effect will lower the temperature at ceiling (and the heat load/fuel bills), as compared to forced air. If you want "shirt sleeve" working conditions, you want radiant floor heating.

You need XPS foam rated for the load, with tube stapled to foam or suspended on the rod depending on the heat loads and building use. The right foam and PEX tubing have no negative affect on slab strength or performance.

You will want a condensing boiler (or two) with proper controls. Mechanical engineers cover a lot of ground and this is a specialized field.

We design and install these systems all over the country and specify all components from the grown up.

Naturally it all starts with a proper heat load analysis.
http://www.badgerboilerservice.com/images/SampleHeatLoadAnalysis.pdf

 

[Shop Specialties]

In floor heat is the only way to go. You only need a third of the BTU as compared to forced air. It will actually be cold at the ceiling with in floor because the heat will start to dissipate at about 8' off the floor. If you generate waste oil you should look at waste oil boiler. I am not sure about Kansas tax credits but you can get up to $1.80 per square foot Federal tax credit by going with a waste oil boiler.

 

[garretttpe]

I have radiant heat in my 30 x 60 10 foot ceiling garage in Northern Maine and insulation under the slab is a must. the is a material called Micro vent (google it) that is cheaper and better then the traditional 2 inch blue board under a slab. the Micro vent product is flexible and will form to the ground and concrete to prevent any voids. I used their product on my garage and I will swear by it.
I was actually told about by my Amish neighbors

I used 170 gallons of oil since I built the garage this summer and it is now the end of march. since adding more insulation in my attic Jan 2nd I have only used 1/8th of a tank of oil 275 gallon tank. If Iwould have had more insulation form day one I would have used not more then 100 gallons I am sure. spend the money on insulation and savings are forever

Larry