Passivhaus Homes Ltd PH15 Modular Building System
Durability Assessment: Minimum 60 Years
Construction System Summary:
Factory precision cut engineered timber “I Studs” are transported to site and stacked before being erected on site constructed foundations. The foundations are site specific depending on site ground conditions. There are three options for the ground floor depending on local ground conditions they are (1) Ground Bearing slab consisting of 150mm RC 28/35 concrete power floated slab with A393 reinforcement mesh with 35mm cover on 500 gauge DPM on 200mm – 300mm Celotex GA400 PIR insulation in two layers on 50mm sand blinded sub- base on Radon Barrier DPM. (2) Ground Bearing slab consisting of 150mm RC 28/35 concrete power floated slab with A393 reinforcement mesh with 35mm cover on 500 gauge DPM on 200mm – 300mm Celotex GA400 PIR insulation in two layers on suspended concrete beam floor with no (or minimum) blocks fitted to reduce embodied carbon. (3) suspended timber (Minimum 150mm void) I beam floor cassette consisting of 360mm “I Beam” underdrawn with Celenit AB/A2 board (Euroclass A2-s1d) mineralized 15mm Wood Wool Board, top of joists are over boarded with OSB3 Deck and Intello airtight membrane. The floors are sat on pile foundation to S.E. design with pile head and cap designed and supplied by RapidRoot. The floor is insulated onsite with wood fibre insulation.
Limits on scope
Maximum 5 storeys for residential use;
Bottom members minimum 150mm above external ground level;
Minimum 47mm drained and ventilated cavity behind external wall claddings;
Adequate sub-floor ventilation must be maintained to the void below the ground floor;
Ground below ground module floor must be sealed to limit moisture within the void, e.g., membrane + 50mm sand blinding.
Sheathing boards used in the construction must be third party approved for the proposed use (e.g., BBA, KIWA, ETA). All fixings to the supporting structure are EJOT STR-H Thermally broken fixings. Relative Humidity in the cavity behind the wall cladding must not exceed 85% for extended periods.
Passivhaus Homes Ltd must be contracted for the design, manufacture, supply and contractor training for the erection of the shell by others:
A chartered structural engineer suitably experienced in the design of this type of structure must be sub-contracted for the structural analysis and design.