I've got a similar job to do around My window reveals ,what's this marmox multipanel of which you speak ?
There is no window frame left/visableThe 40mm Marmox arrived.
All the bits cut. Yet to stick when I decide a) what to use, i.e Soudafoam Low Expansion or something else and b) whether to dig out the existing cheapo foam and use Illbruck FM330. Need to tweak the little infill bit on the sill at the end by the window.
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Mitred the soffit section:
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There is no window frame left/visable