One of the difficulties you face today is that there is perhaps too much choice when it comes to choosing the right product or tool for any project or activity.

When it comes to buying fasteners for rigid foam insulation boards there are so many different systems, sizes, materials, and methods that it can make the simple task of attaching insulation appear far more complicated than it needs to be.

All it means is that manufacturers are working hard to ensure that they have all bases covered so that there will always be a perfect fastener available for every project.

Here’s our list of fasteners and accessories, from best buys to best to avoid, to help get you through the maze.

#1. Best All-round Fastener for Timber and Steel

Termo-Fix 6H-NT – fischer international  

Fischer International produces a wide range of specialist fixings at a reasonable price. The Termo Fix range is a polyamide sheath/washer combo with a pre-fitted steel screw designed to fix rigid foam insulation boards up to a thickness of eleven inches.

Installation onto a timber substrate is simple. Just push the screw through the insulation then use a driver to take it home. The washer grips the insulation flat against the face. It can also be used in masonry with an appropriate plug.

Average cost: $90-$120 (dependent upon depth required) for a pack of 100.

Can it be used with all types of rigid foam?


#2. Best Concrete Fastener

Plasti-Grip Masonry Fastener 

The Plasti-Grip masonry fastener is ideal for fixing insulation board to concrete walls or for holding boards while adhesive is curing. The plastic core helps to stop thermal bridging, which is when a break occurs in the insulation, i.e. when there is direct contact through the insulation panel, transferring energy.

Extremely easy and quick to install, simply drill then hammer in. No need for screws or adhesives.

Best for fixing insulation board to concrete basement or crawl space walls. Can be used in masonry but may struggle to hold in old mortar. If you are using adhesive to fix boards to a wall, it is possible to use just two Plasti-Grip masonry fasteners to hold an 8 foot board in place until it has cured. 

If you find you need more than two fixings to hold the board while the glue is trying to do its job then you either need to upgrade the board adhesive, or simply resort to relying solely on mechanical fixings.

With one person drilling and another hammering the job of mechanically fixing foam board to a wall with this fastener can go very quickly.

Average cost $100-$130 (dependent upon depth required) for a pack of 250.

Can it be used with all types of rigid foam?


#3. Best All-round Fastener Accessory

Thermal Grip 2” Prong Washer 

Good all-round foam board fastening product at a reasonable price.

For use with all types of foam board insulation it has two prongs to hold it in place on the face of the insulation to leave both hands free for using power tools. It is a proprietary washer that pulls flat against the face of the insulation to protect the air seal of a building and it is designed not to tear foil facings of polyiso.

Whether you are drilling through the board to fix to masonry, using self-drilling ceramic coated screws to fix to metal, or self-drilling screws to fix to timber studs, these washers are designed not to let the screw head pull through.

Best for fixing continuous insulation boards to timber or metal studs/beams when an air barrier is specified.

Average cost $70 for a pack of 1000 (screws extra).

Can it be used with all types of rigid foam?

Yes, but especially recommended for use with polyiso.

#4. Best Air and Vapor Seal Fastener Accessory

Grip-Deck Tube Seal Accessory 

This solves the problem of sealing both an air and vapor barrier when fixing foam board insulation.

The tube seal fits around either a size 8 or 10 fixing and compresses against the timber or steel stud and the back of the washer thereby creating a water and airtight seal. Ideal when fixing blind and can be pre-ordered to arrive ready assembled with the supplier’s washer and screw.

Average cost: Price on application to specialist supplier dependent upon requirements.

Can it be used with all types of rigid foam?


#5. Best External Basement Fastening System

Nail Gun Fasteners 

These are sold as a rapid fixing system ideal for polystyrene foam board insulation. The nails are set into a plastic washer and sheath and are fired directly through the board into the concrete, steel or masonry substrate with a pneumatic nail gun.

No drilling is required, and the pneumatic nail gun gun is said to be five times faster than drilling and fixing. 

The downside in this case is that the fixing gun costs $1800 to buy or $250 a week to hire with the fixings coming in at $209 for a pack of 100 plus $40 for the cartridge to drive the nails home.

If time is money then that may offset the cost, however this is likely only a good choice for high volume applications, for large tract-housing contracts.

Can it be used with all types of rigid foam?

Recommended for all foam board insulation products.

#6. Best Budget Fasteners (or products to avoid if at all possible).

Local Home Improvement Store Fixings 

We get it. Energy prices are sky high, and you need to save money as well as energy to be able to live your best life. There are ways of fixing insulation boards that won’t break the bank but beware of false economies.

Yes you can use roofing nails and wood screws as long as they are partnered with washers of a minimum of a half inch diameter. Plastic cap nails and cap staples are also a budget alternative, but you will need to use more of them to ensure a sound fixing and they could pull through a polystyrene foam board.

The best method of fixing with wood screws or roofing nails would be to use them to fix either treated timber battens or metal framing to the surface of the insulation board. The battens would act to pinch the board to the rafters, wall stud or sheathing. Used with an adhesive this would also help to maintain a seal.

Average cost $40 for a pack of 50 6” screws plus $2 for the metal washers

Can it be used with all types of rigid foam?



Evan has decades of experience as a project manager for large-scale commercial renovation home-building projects throughout the US. Currently, Evan runs a successful construction management company in Virginia.

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