Private Residence
RC House
Accoya Timberclad Facade System Engineered for Tropical Heat and Humidity Stability
Architect
Studio TonTon
year
2020
location
West Jakarta, Indonesia
size
850 m²
The Brief
Project Overview
RC House integrates Accoya Timberclad beneath a continuous skylight in Jakarta, exposing timber surfaces to direct solar gain, thermal cycling, and sustained humidity.
The risk was long-term movement and façade distortion under tropical stress.
Objective
The objective was to validate modified timber façade stability by proving:
• Line straightness across extended façade and ceiling runs
• Joint tolerance consistency under expansion cycles
• Warping resistance under solar heat exposure
• Moisture resilience in fluctuating humidity conditions
This project confirmed that façade performance in the tropics requires engineered material modification, not untreated solid timber.
The Constraints
Skylight Heat and UV Exposure
Timber sat directly beneath a continuous skylight. Solar gain and UV exposure increase movement risk, including cupping, joint opening, and fastener stress. Material choice had to prioritize dimensional stability.
Jakarta Humidity Cycling
Repeated moisture cycling can distort ceiling lines and open facade joints over time. Movement control was a performance requirement, not a finish detail.
Long Linear Profile Runs
Extended parallel profiles amplify small errors across distance. Straightness depended on strict fabrication tolerances and a stable, level substrate.
The Engineering
Accoya Timberclad Performance Mechanism
Accoya was selected for its acetylated chemistry, which reduces moisture absorption and materially lowers swelling and shrinkage. Movement control is the core mechanism protecting facade straightness under heat and humidity cycling.
Ventilated Rainscreen Strategy
Timberclad was detailed as a ventilated assembly with airflow gaps to prevent trapped moisture and stabilize the back of boards under tropical exposure.
Connection and Movement Allowance
Profiles were mechanically fixed with concealed attachment where possible. Junctions included controlled movement allowances so thermal expansion does not force buckling or joint opening under cyclic stress.
Straightness and Substructure Control
Long runs were precision-machined and installed against an aligned substructure. Straightness was treated as a fabrication and installation requirement, not a finishing correction.
The Products and Materials
The Results and Insights
Long-Run Dimensional Stability Achieved
Ceiling and façade profile alignment remained straight under skylight-driven heat exposure and daily moisture cycling.
No visible warping, joint separation, or spacing drift has been observed under normal use.
Tropical Envelope Performance Validated
The project confirmed that the Accoya Timberclad façade and ceiling system can maintain geometric control in Jakarta’s combined heat and humidity conditions when installed with ventilation gaps and movement allowances.
Architectural Rhythm Preserved
Extended linear runs retained consistent spacing and shadow-line continuity, reinforcing that straightness is a fabrication plus installation outcome, not a finishing correction.
Mechanism Insight
In tropical modern architecture, precision is achieved through movement control:
Accoya reduces material movement risk.
Timberclad defines repeatable installation logic.
Together, they protect architectural intent.
Location
West Jakarta, Indonesia
INDONESIA
Frequently Asked Questions
Got a question unanswered? Speak to our team.
Why was Accoya chosen instead of conventional hardwood?
Conventional hardwood expands and contracts more under heat and humidity. Accoya’s acetylation process reduces moisture absorption, resulting in significantly lower dimensional movement and improved long-term stability.
Can timber be installed directly beneath a skylight in Jakarta?
Yes, but species selection and detailing are critical. Accoya’s stability allows it to perform under direct heat exposure and UV cycling, provided ventilation gaps and movement allowances are correctly engineered.
How does Timberclad manage moisture?
The system includes ventilation cavities behind profiles and controlled fixing methods. This allows air circulation and reduces trapped moisture, preventing distortion and premature deterioration.
Is Timberclad suitable for both interior ceilings and exterior facades?
Yes. With the correct species and detailing, Timberclad performs across vertical, horizontal, and overhead applications in tropical climates.