FabCab

05/22/2026

"SIPs will rot if moisture ever gets in."

It's one of the most common concerns we hear.

EPS insulation, the solid foam core inside Structural Insulated Panels, does not absorb water. It is not fiberglass batt. It does not wick, hold, or migrate moisture through the core the way cavity insulation does.

Moisture risk in any wall assembly comes from air movement through gaps at transitions. Joints, window openings, penetrations. SIPs construction reduces the number of those gaps and concentrates the ones that remain at predictable, sealable locations.

That does not mean detailing does not matter. It does. Proper joint sealing and transitions at windows and roof connections are critical in any high-performance assembly.

But the claim that a SIPs wall will silently rot from a single leak does not hold up against how these systems actually behave.

→ The full explanation of how SIPs manage moisture: https://hubs.ly/Q04hh4fX0

05/16/2026

"SIPs are just foam and OSB. Won't they go up in flames and release toxic fumes?"

No. And the claim does not hold up under scrutiny.

Premier SIPS are tested to 1-hour fire-rated wall assembly standards (ASTM E119). With approved gypsum detailing, they meet or exceed code-required fire performance, including Wildland Urban Interface (WUI) requirements where stick-frame assemblies often need multiple additional product layers to reach the same compliance level.

On the off-gassing claim: EPS and GPS insulation cores are chemically inert. They do not release harmful gases when exposed to heat. The rigid foam is also treated with flame retardant during manufacturing.

There is another advantage most people miss. SIPs buildings are inherently airtight. That limits the oxygen that fuels fire spread. And unlike vented attics and eaves in stick-frame construction, SIPs eliminate the paths that embers exploit during wildfires.

Every building material will eventually degrade in a sustained fire. The question is how your assembly performs before it gets there. SIPs meet the codes.

More common SIPs questions answered: https://hubs.ly/Q04gDfTT0

10/28/2019

Happy to be included in a new book by Sheri Koones previewed by the Seattle Times

Prioritizing design and purging possessions, these Washington homeowners have found lots of up sides to downsizing.

10/23/2019

Our 2 bedroom/2 bathroom ModCab home on Vashon Island has the right mix: Tons of natural light, universal design, open living/dining/dining/kitchen with three panel folding door for indoor/outdoor living.

02/04/2019

Happy to be included in this article by Sheri Koones

There is still a great deal of confusion about prefabrication. This will clarify some of the terminology and information homeowners might want to know to build their own prefabricated home.

06/08/2018

Thanks to Home Builder Digest for including us in this list!

Famous American architects — from Buckminster Fuller to Frank Lloyd Wright — have investigated and promoted the promise of prefabricated homes. But it’s only in the last few decades that the industry has really come into its own. Today’s prefab and modular homes are stylish, durable, and hig...

05/17/2018

This is our second home on Camano Island. The original structure was a dark, drafty 322 sf fishing cottage cabin. In its place stands a tomato red cabin that is now used year round.

12/11/2017

12/11/2017

Great tech summit put on by TecHome Builder.

05/23/2017

Regardless of your age or abilities today, this compelling NYT article echoes a message we share with our clients, which is it's always better to make plans sooner rather than later. Includes link to find CAPS specialists near you. https://www.nytimes.com/2017/05/19/health/aging-in-place-contractors.html

Virtually all single-family homes lack features needed to accommodate aging owners’ limitations. But there are specialists prepared to help fix that.