A precast modular foundation system offers many advantages in building development and performance, but also removes the need and risk of site-based technical assessments during construction. Sweden’s Isolergrund offers this new element to building design.
The foundation’s structural design integrity, its dimensions and constituency have been assessed and formulated in the factory – all that remains is for it to be positioned and assembled correctly on site, following numbered directions and certified complete by testing. Although modular foundations are not suitable in all cases they offer a rapid, standardised and guaranteed solution that compliments both traditional and modular building techniques offering significant cost savings, reduced environmental impact and a certified foundation solution.
Unlike traditional foundation formation, issues such as damp penetration, cold bridging or land contamination issues can all be designed out by correctly specifying an offsite modular foundation system. This leaves the building designer free to focus on building development rather than foundation construction risks. Modular foundations provide:
Rapid, ‘right-first-time’ construction. Modular foundation assembly on-site is far quicker than by traditional methods and as the product is ‘dry’ there is no waiting time for moisture levels and product stabilisation to occur. Typical construction time savings in excess of 70% are further benefited from the fact the modular foundation assembly is unaffected by inclement weather.
BS5250 compliance. As property thermal performance increases the temperature differential between the internal building environment and the foundation increases , leading to a propensity for high and saturated humidity levels at the underside surfaces of the ground floor structure. BS5250 calls for a value no greater than 80% RH. This can currently only be guaranteed by introducing a negative pressure void system as provided by the Isolergrund system.
Reduced emissions foundation. Through the utilisation of high strength, micro-fibre reinforcement, in lieu of steel, close structural design phase co-ordination and precisely-controlled production dimensioning, the Isolergrund modular foundation system dramatically cuts embodied CO2 emissions and those associated with site construction and waste.
Modular foundations also improve thermal performance of the building development by reducing heat loss to the ground. The Isolergrund foundation system introduces an additional thermally insulated sub-structure lining, avoiding all cold bridging and preventing unwanted cold air transfer to floors and building joints, particularly important when building in modular formation. They also solve inherent air permeability issues associated with building on traditional foundations.
Modular foundations can incorporate a crawl space which gives rise to several key advantages: freedom to add or alter ground penetrating services positions in the future, ability to introduce negative pressure zone to guarantee compliance with BS5250, facilitates pre-casting service entries for district energy networks, offers the ability to measure temperature and humidity beneath the building ground floor.
Precast reinforcement inherent within modular foundations designed specific to the building development, negates the requirement for any site-based technical assessment. Plus the precast fabrication eliminates site health and environmental risks associated with on-site production and at the same time reduces site waste and waste management.
Thermal Insulation and contamination and damp protection can be integrated into the modular foundation system helping to ensure the building’s ultimate performance fully meets or exceeds its regulatory and comfort specification criteria.
A site investigation is usually needed for the engineer to understand what the ground is like. Very poor ground may mean you need to augment the modular system with a piled sub-structure. The modular foundation needs a hardcore sub-base to level the ground and this stone should be mechanically compacted and designed to be freely drained.
For more information visit: https://isolergrund.uk
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