What are the RV load bearing requirements an AC unit?
The RV roof must be strong enough to hold 88 pounds and remain level without collecting water. Around the 14 ¾-inch opening, wood framing at least ¾ inch thick should be added to support the air conditioner and prevent roof crush.
Preparing the Roof
Before installing the air conditioner, confirm that your RV roof can safely support the unit’s weight and remains flat enough to prevent water pooling.
If the installation hole is not already cut, contact your RV manufacturer for guidance on how to properly create a 360 × 360 mm (14 ¾ × 14 ¾ in) opening.
Reinforcing the Opening
Frame the opening with wooden blocks at least 20 mm (¾ in) thick.This reinforcement prevents the roof from compressing under the mounting bolts and helps stop conditioned air from leaking into the ceiling space.
Roof Thickness by Model
T3500 model: roof must be 25–85 mm (1–3 3/8 in) thick.
A3501 or A3800 non-ducted: roof must be 25–145 mm (1–5 5/8 in) thick.
A3501 or A3800 ducted: roof must be 75–150 mm (3–6 in) thick.
If your roof is thicker than the maximum listed for your model, a Thick Roof Bolt Kit can be purchased from Houghton or your local distributor.
Corky Lorenz
November 4, 2025