Akfix 805 Gap Filler Polyurethane Expanding Foam Sealant - 12 Pack

Our review of the Akfix 805 Gap Filler finds it best suited to DIYers and trade pros who need a waterproof, fast-curing foam for filling windows, doors and common building penetrations. The single-component, moisture-curing polyurethane in the 12-pack delivers rigid, over-paintable foam that bonds to most construction substrates, and the included straw adapter makes targeted application possible; the main reason to buy is dependable adhesion and a quick 3-5 minute tack time that lets jobs move forward without long waits.

Key Features

• Single-component formulation: The foam expands and cures without mixing, simplifying application for both small repairs and larger sealing tasks.
• Moisture-curing action: Cures reliably in damp conditions so gaps around window and door frames seal even in less-than-ideal environments.
• Included straw adapter: The straw allows more precise dispensing into joints, cavities and around pipes, reducing waste when used carefully.
• Waterproof and paintable: Once cured the foam is waterproof and can be trimmed, shaped and painted for a finished appearance in indoor or outdoor work.
• Ozone-friendly propellant: The aerosol does not use propellant gases harmful to the ozone layer, addressing environmental concerns during use.
• UL certified safety: The product meets UL standards, which provides an added level of manufacturing and safety assurance.

Who It's For

The Akfix 805 is ideal for homeowners tackling weatherproofing around window and door frames, builders sealing service penetrations, and DIYers filling larger gaps and cavities where a rigid, paintable result is wanted. The 12-pack format suits small contractors or anyone who plans to do multiple jobs over time and needs a consistent supply.

Those who need ultra-precise spray control or have limited experience with aerosol foams may want to test a single can first; some buyers report variable sprayability that can make dispensing a little difficult until users become familiar with the trigger pressure and technique.

Pros & Cons

Pros

• Strong adhesion to most building materials provides a durable seal for gaps and penetrations.
• Fast tack and cure times let work continue within minutes and full cure in about 24 hours for trimming and painting.
• Waterproof and paintable finish is practical for both interior and exterior applications.
• 12-can pack gives value and consistency for multiple jobs or professional use.

Cons

• Sprayability can be inconsistent; some users find the can difficult to control without practice.
• Will not adhere to polyethylene, Teflon, silicone or oily/contaminated surfaces, requiring surface prep or alternative products for those materials.

Specifications

Product type	Polyurethane expanding foam sealant
Package	12 cans, 12 oz each
Curing	Moisture-curing; tack in 3-5 minutes, full cure ~24 hours
Application areas	Window and door frames, gaps, joints, cavities, pipes, electrical outlets
Finish	Waterproof and paintable when cured
Storage	Store vertical; avoid >50 C; keep between +5 C and +25 C for best shelf life
Safety	UL certified; harmful by inhalation, use ventilation and PPE

Our Verdict

The Akfix 805 Gap Filler is a practical, cost-effective choice for sealing and insulating work where a rigid, paintable foam is required; it suits homeowners and small contractors doing repeated jobs thanks to the 12-pack. It is not perfect for every surface and takes some practice to control the spray, but where adhesion, waterproofing and a quick cure matter, it offers solid value and reliable results.

Frequently Asked Questions

How long until the foam can be trimmed?
The foam has a tack time of 3-5 minutes and can be trimmed and shaped after about 24 hours when fully cured.

What surfaces will the foam not stick to?
It will not adhere to polyethylene, Teflon, silicone or surfaces contaminated with oils, greases or mold release agents; those surfaces need special prep or a different product.

Is it safe to use indoors?
Use only in well-ventilated areas and wear gloves, eye protection and protective clothing because the spray can irritate eyes, skin and the respiratory system.