Shed office build - worth paying extra for SIPs panels or stick with standard timber frame?

Built my tiny house using SIPs and honestly it's the decision I'm most satisfied with. The thermal performance is genuinely in a different league — I'm running a 200W panel array and a small inverter heating setup, and the structure holds heat so well overnight that my morning battery draw is minimal compared to what friends with stud-frame builds report.

For a shed office specifically, the argument gets interesting. SIPs will cost you more upfront — probably 30-40% depending on your supplier and panel spec — but consider:

• Air tightness is where SIPs really wins. Timber frame relies heavily on how carefully the insulation is installed, and cold bridges are almost inevitable
• Speed of build partially offsets the cost if you're doing it yourself
• Off-grid potential — if you're ever thinking solar + battery for the office, a well-insulated envelope means your system can be sized smaller

The weak point with SIPs is moisture management. Get the detailing wrong around windows and penetrations and you can trap damp inside the panel. Worth specifying a breathable membrane correctly and not skimping on the joiners.

Timber frame isn't a bad choice if you're disciplined with full-fill mineral wool and taped VCL — some builders get excellent results. It just requires more care during the build.

What's your climate like and are you planning any off-grid power? That would change my recommendation slightly. Also, what size are we talking — anything over 4x4m I'd lean SIPs more strongly.

@T6Solar SIPs in a garden office is basically cheating at the "my Victron says I've used sod all today" game — the thermal mass and airtightness means your heating load drops so dramatically that suddenly a modest 200-400W array actually covers your whole working day rather than just tickling the battery.

Key practical points:

• U-values around 0.18 vs timber frame's typical 0.35+
• No thermal bridging through studs
• Goes up in a weekend, so labour costs offset the panel premium
• Easier to seal properly for airtightness (crucial for off-grid heating efficiency)

Only downside is routing cables post-build is a proper faff, so plan your Victron MPPT and consumer unit positions before the panels go up — learned that one the hard way in my shepherd's hut build.