Floor insulation question

[palikona]

I’m designing a two story 3,000 sf medical office in FL. Level 1 is an open parking lot under the clinic above. Level 2 is concrete/metal deck on steel beams. I have an exterior suspended ceiling dropping down below the deck. Do I need to provide insulation under the slab in the exterior ceiling plenum?

 

[RLGA]

Yes. The FBC Energy Conservation Code requires the "opaque portions of the building thermal envelope" to comply with the code's insulation requirements. Florida is predominantly in Climate Zone 2A, which requires R-6.3ci (continuous insulation) for mass construction, which concrete on a metal deck would likely be considered. You can also use the U-Factor method, which requires the entire floor/ceiling assembly to have a maximum U-0.107. If the project happens to be in one of the 1A Climate Zones, the values are NR (not required) for the R-Value method or U-0.322 for the U-Factor method.

 

[palikona]

Thank you. From a constructability point of view, what is the best way to provide that horizontal continuous insulation under the deck, in the plenum? Rigid polyiso attached to the underside of the slab?

 

[Yankee Chronicler]

Polyisocyanurate is flammable. You need to consider the type of construction, and whether flammable insulation is allowed.

 

[redeyedfly]

Polyisocyanurate is flammable. You need to consider the type of construction, and whether flammable insulation is allowed.

What type of construction doesn't allow flammable insulation?

 

[Paul Sweet]

Flammable insulation is allowed, but needs to be protected by a thermal barrier of 1/2" gypsum board or equivalent.

 

[bill1952]

Flammable insulation is allowed, but needs to be protected by a thermal barrier of 1/2" gypsum board or equivalent.

Would you accept an intumescent coating?

This one tested for 15 minutes: https://shop.rdrtechnologies.com/F10-Fire-Retardant-Paint-for-Foam-p/f10e.htm

 

[palikona]

Polyisocyanurate is flammable. You need to consider the type of construction, and whether flammable insulation is allowed.

Hi,
The construction type is 2B. I can use that insulation, correct? Or is there a better type for this application?
Thanks

 

[Yankee Chronicler]

You don't need insulation under the lower slab if you use an equivalent envelope approach to energy conservation. In other words, add enough insulation elsewhere in the envelope to allow the building to achieve a passing score on a COMCheck evaluation.

If you prefer to insulate under the slab, there are choices other than polyiso.

Comfortboard® 80 rigid mineral wool continuous insulation sheathing board | ROCKWOOL

ROCKWOOL Comfortboard® 80 is a rigid exterior insulation board, providing a continuous layer of insulation around commercial or residential building envelopes.

www.rockwool.com

Thermafiber® RainBarrier® Dark™ | Owens Corning Insulation

Thermafiber® RainBarrier® Dark™ continuous insulation with a bonded black facing designed for exceptional performance in rainscreen & cavity wall applications.

www.owenscorning.com

Would you accept an intumescent coating?

This one tested for 15 minutes: https://shop.rdrtechnologies.com/F10-Fire-Retardant-Paint-for-Foam-p/f10e.htm

I wouldn't. https://sbcindustry.com/fireprotectionfloorsqa

 

[jar546]

I’m designing a two story 3,000 sf medical office in FL.

Where in Florida? They have different climate zones that may alter the answer.

 

[palikona]

Where in Florida? They have different climate zones that may alter the answer.

Tampa

 

[palikona]

You don't need insulation under the lower slab if you use an equivalent envelope approach to energy conservation. In other words, add enough insulation elsewhere in the envelope to allow the building to achieve a passing score on a COMCheck evaluation.

If you prefer to insulate under the slab, there are choices other than polyiso.

Comfortboard® 80 rigid mineral wool continuous insulation sheathing board | ROCKWOOL

ROCKWOOL Comfortboard® 80 is a rigid exterior insulation board, providing a continuous layer of insulation around commercial or residential building envelopes.

www.rockwool.com

Thermafiber® RainBarrier® Dark™ | Owens Corning Insulation

Thermafiber® RainBarrier® Dark™ continuous insulation with a bonded black facing designed for exceptional performance in rainscreen & cavity wall applications.

www.owenscorning.com

I wouldn't. https://sbcindustry.com/fireprotectionfloorsqa

So the roof and wall construction I’ve designed meets the requirements for Florida energy codes, but the concrete/metal deck in question is Level 2, with an open air parking lot of 7 spaces below. Will that be a problem in Florida? Or do I need to insulate that slab on the underside, where I have an exterior dropped ceiling above the parking lot.

 

[Yankee Chronicler]

So the roof and wall construction I’ve designed meets the requirements for Florida energy codes, but the concrete/metal deck in question is Level 2, with an open air parking lot of 7 spaces below. Will that be a problem in Florida? Or do I need to insulate that slab on the underside, where I have an exterior dropped ceiling above the parking lot.

Tampa is in Hillsborough County. According to Table C301.1 of the Florida Energy Conservation Code that's climate zone 2A --with an asterisk, meaning it's a warm-humid climate.

If you then look at Table C402.1.3, the requirement for mass floors is R6.3ci. I think the construction you described meets the definition of mass floors, so if you are following the prescriptive approach you have to insulate the floor to R6.3 as a continuous layer.

If you don't want to put insulation on the underside of the slab, you can increase the insulation in the walls and/or roof by enough to pass a COMCheck evaluation with no insulation in the floor, as spelled out in C407.3.

Are you an architect? You don't know how to apply the energy conservation code?