So we want the van to have a feature 'panoramic' skylight, and figured we want it to be as big as possible, over the rear bed area so we can lie in bed and stargaze (how romantic... boke...)
Again there's been much research into materials and methods here. Choices boiled down to between a triple-glazed polycarbonate 'Mardome' roof dome or a custom made double-glazed glass unit.
Various attributes made glass the better option for us; it allows the roof of the van to be as streamlined as possible (the polycarbonate units are way more bulky), it has better sound insulation (36 LiA compared to 62 LiA)*, and its thermal properties are more favourable (u-value of 1.0 W/m2 K compared to 1.8W/m2 K)**
*LiA = A-rated sound intensity level in db = how noisy stuff is, weighted to how humans actually hear noise.
**u-value = the rate of heat transfer... So a higher number means more heat is lost through the skylight.
Mardome roof light |
As the glass is on a vehicle it must be either toughened or laminated for safety (and really should be e-marked... but hey ho...) The unit we have specced (this will be custom made) consists of an outer layer of 4mm toughened Planithern 4S glass, a 20mm argon spacer, and an inner 6.4mm laminated glass. The Planitherm offers "excellent solar control properties, reduced glare and enhanced thermal insulation". So it reflects the sun and keeps the van cooler in hot weather.
We will fabricate a steel frame welded into the structure of the van to accommodate the window unit. The frame will be trimmed on the inside to prevent cold bridging from the outside which would otherwise cause condensation. Inside the van there will be a channel built into the frame to accommodate a custom made blackout window blind.
How big can we make this skylight? HUGE. We’ve ordered a 118x112cm double glazed unit from www.sealedunitsonline.co.uk. It might take up to 28 days to arrive though.
Above the kitchen area there be a Fiamma 28F turbo fan roof vent, which will ensure the van is well-ventilated and let in even more natural light.
Fiamma 28F Roof Vent |