Loft Conversion & House Refurb, Herts.
House Area: 335 m2 / Loft Conversion: 50 m2.
This project was a major ‘roof off’ loft conversion with additional refurbishment and upgrades to the existing house. The house remained in use during the works; requiring a fair bit of ‘lateral thinking’ and sequencing to minimise disruption
The roof extension was designed to exploit maximum available space allowed within statutory guidance [50m2]. The extra space provided two additional large bedrooms and shower room to give the family’s eldest sons independent space of their own.
The existing timber roof structure was completely removed and a new steel frame structure craned into place. Works were protected by a full scaffold ‘wrap’ and ‘tin hat’ roof giving total weather protection during the autumn>winter build [still v. chilly!], not a cheap option but essential to allow the build to continue efficiently and the house to remain occupied full time.
Roof pitch was increased to give maximum flexibility in the layouts and designed so that minimum alteration works were needed to accommodate the new second floor staircase.
Roofs and floors were insulated with solid mineral wool batts; giving a ‘guaranteed’ U value of about 0.22 W/m2k. Roofs were further insulated with an additional unde rafter layer of Tri-iso ‘Super 9′ [now 'super 10'] multi-foil insulation.
Multi-foil insulation is made up of multiple layers of alternating metallised foil and fleece, overall thickness about 10mm and giving the same thermal performance of about 200mm of mineral wool [manufacturer's claim]. This gave the new roof a theoretical U value of around 0.1 W/m2k – ‘Superinsulated’! There’s a lot of ‘heated!’ debate about the actual performance of multi-foil – that testing methods do not replicate real-world heat transfer physics and manufacturer’s performance figures can not be trusted, but I think in situations where headroom needs to be maximised they offer a great ‘back up’ to supplement more solid insulation.
Tags: built work, conversion, house.extension