Fire retardant treated wood for WUI and Chapter 7A projects

Pressure-impregnated FRT lumber, plywood, siding and decking with Class A flame spread for homes and commercial builds in fire zones.

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Wildfire-zone building
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Ignition-resistant materials are required across California's wildland-urban interface. We stock them

FRT wood slows ignition, limits flame spread and reduces smoke, helping siding, decks and framing meet Chapter 7A and local WUI codes.

fire safe

Class A rated

Flame spread index of 25 or less (ASTM E84).

Exterior grade

Leach-resistant treatment for siding and decks.

Code listed

ICC-ES and CA State Fire Marshal listings [CONFIRM].

Ready to build

Cuts, nails and finishes like untreated lumber.

How FRT wood works

Treated through, not coated on

Fire retardant is pressure-impregnated deep into the wood, then kiln-dried, so protection does not wear off like paint. Exterior grades [CONFIRM brand] resist leaching in rain and UV.

Every piece carries a third-party grade stamp [CONFIRM listing agency] showing flame spread, smoke developed and exterior or interior rating.

63+ species in stock

Solid and engineered wood products in over 63 species, veneer in over 203.

Established 1920

Over a century in the wood trade, with custom millwork and finishing in-house.

Metal detected & kiln dried

Every reclaimed board is metal-detected, kiln dried and milled.

Samples & trade pricing

Samples on request; architects, builders and designers welcome.

What we stock

FRT lumber, plywood and siding

Dimensional lumber, plywood sheathing, exterior siding and deck boards, plus treatment of our own profiles on request [CONFIRM].

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Luna Sharp HF-FR fire retardant cladding

FRT lumber

Interior and exterior fire retardant treated dimensional lumber and plywood for framing, sheathing, eaves and soffits.

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FRT siding

Exterior-rated fire retardant siding and decking boards for ignition-resistant exterior walls and decks in WUI zones.

Fire retardant treated products

Exterior- and interior-grade FRT wood for ignition-resistant construction. Listings, brand and stocked sizes to be confirmed before publication.

Framing and sheathing

FRT lumber and plywood

Pressure-impregnated dimensional lumber and plywood sheathing with a Class A flame spread rating for eaves, soffits, decks, walls and roof decks in wildland-urban interface zones. [CONFIRM brand and listings]

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Fire retardant Luna Triple HF-FR cladding
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Ignition-resistant exteriors

FRT siding and trim

Exterior-rated fire retardant siding and trim that resists leaching in rain and UV, for Chapter 7A exterior wall assemblies. [CONFIRM]

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Decks in WUI zones

FRT decking

Fire retardant treated deck boards for decks within the defensible space of homes in California fire zones. [CONFIRM]

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SaferWood project
Luna Sharp HF-FR fire retardant cladding
Class A

Flame spread 25 or less, ASTM E84

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Exterior grade

Leach-resistant treatment

Fire retardant Luna Triple HF-FR cladding
Interior grade

For enclosed framing and millwork

SaferWood project
Custom treatment

Our own profiles treated to order

Flame spread

Class A

Standard

ASTM E84

Rating

Exterior

Code

Ch. 7A

Testing and documentation

Test reports on file

The fire-retardant treatment on our thermally modified products is backed by independent ASTM, ULC and UL test reports. Treated products include VG Hemlock Aegis Reserve, Western Red Cedar, Radiata Pine cladding and decking, VG Hemlock cladding and thermowood pergolas. Final classification depends on species, profile, thickness and installation; ask for the report that applies to your project before specifying.

The treatment slows ignition and flame spread; it does not make wood fireproof.

30-minute extended surface burning test under sustained heat. Tested September 2019, August 2017 and February 2015.

Surface burning characteristics, focused on permanency of the treatment. Tested February 2016.

Fire resistance adjusted for individual components: 17 minutes at a 14% load factor.

Effects of the treatment and elevated temperature on softwood lumber strength. Tested May 2018.

Flexural properties of OSB and plywood, including at high temperature. Tested February 2024 and December 2017.

Moisture absorption (hygroscopic properties). Tested November 2017.

Corrosion of metal fasteners in contact with treated wood. Tested June 2018.

Volatile organic content: 0.06% VOC.

Potential heat of combustion: 7,729 Btu/lb on 1/2 in SYP plywood and 8,247 Btu/lb on 7/16 in OSB. Tested October 2021.

Canadian surface burning test: Class A on SPF sawn lumber and 3/8 in OSB. Tested February 2016.

Chemical emissions: GREENGUARD Gold certified.

Fire code questions

Common questions

We can review your plans against Chapter 7A requirements before you order.

No. It is ignition-resistant: it chars slowly and limits flame spread, giving occupants and crews more time.

Yes, if you specify exterior-grade FRT. Interior grades leach in rain and lose their rating.

Thermally modified wood is dense and slow to ignite but is not rated. Use FRT where code requires it.

Ask us. Some reclaimed and thermowood profiles can be sent for treatment on a project basis [CONFIRM].

No. It is real wood treated to resist ignition and slow flame spread. It is not non-combustible or fireproof.

Exterior cladding, decking, fencing, gates, pergolas, trellises, soffits and architectural elements, and interior products such as paneling.

Yes. Send drawings with species, profile and application and we will recommend a tested product and supply the matching test report.

Yes, we ship worldwide. Orders go by freight across the US and overseas, with weekly truck delivery across Los Angeles, Orange County and San Diego.

Building in a fire zone?

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