Roof Deck Spray Foam in Clearwater, FL

Roof deck spray foam means insulating the underside of the roof sheathing instead of the attic floor. In a lot of Clearwater-area homes the air handler, the ductwork or both sit in the attic. With the insulation on the floor, that equipment spends every summer afternoon in a space hotter than the air outside, and any duct leak blows cooled air into it. Spraying foam on the roof deck turns the attic into a semi-conditioned space so the equipment and ducts work in much milder air.

How it differs from a normal attic

A standard Florida attic is vented: air moves in through the soffits and out at the ridge, and the insulation sits on the ceiling. With roof deck foam, the soffit and ridge vents are closed off, the foam is sprayed between the rafters or trusses against the sheathing, and the attic becomes part of the insulated volume of the house. The old floor insulation can stay in some cases, or it can come out to make the attic usable for storage. The quote spells out which.

The code side

Florida's residential code covers this setup in section R806.5, which sets the conditions for unvented attic and unvented rafter assemblies. The prescriptive energy code number for ceilings in climate zone 2 is R-38, and the foam thickness has to be planned with that and the unvented attic rules in mind. Your building department has the final say on permitted work. We size the foam thickness to the plan and write it on the quote so you, and the inspector if a permit is pulled, can see what is going in.

Open-cell or closed-cell under the deck

Under a pitched roof with standard rafters or trusses, open-cell foam is the common choice: it costs less per square foot, expands to fill the bays, and gives a roofer the chance to find a leak because water passes through it. Closed-cell suits low-slope roofs, shallow rafters and spots where more R-value is needed in less space. Some roofs get a mix. On every job the quote names the foam type and thickness for each section of the roof.

Before we spray, the roof gets a look

Foam will hide the underside of the deck, so we check it first for stains, soft spots, nail leaks and damaged sheathing. If the roof is near the end of its life, it often makes sense to replace it before foaming, and some homeowners time the foam job right after a reroof. Shingle manufacturers have their own positions on foam under the deck; ask your roofer or check your roof's warranty terms before you commit.

Air and humidity once the attic is sealed

An unvented attic is no longer flushed with outside air, so it shares air with the house. We talk through how that is handled for your home, which may involve the HVAC contractor. Humidity control is the AC's job; the foam's job is to stop the attic from heating up and to keep humid outdoor air from leaking in through the roof line.

Is it worth it?

It costs more than topping up the attic floor. HomeGuide's range for foam under a roof deck is $1,500 to $9,000, and Fixr lists $2,500 to $12,000 for foam in an existing attic. If your ducts are in the attic and your upstairs never cools, or you want a cooler attic for storage, it is worth pricing. If the air handler is in a closet and the ducts are in the slab or interior soffits, adding to the attic floor usually wins on cost. We will tell you which way we would go and why.

Get a free estimate or call (727) 286-3704 to have us look at your roof and attic.