Hi all I have a thirties house with original T&G redwood pine flooring (sanded back ready to varnish). I have knocked through and recently converted the adjacent garage into living space. It has a newly laid concrete base with a DPM and a layer of SLC on top. It is big, about 70m2 I have matching new redwood T&G (currently acclimatising), so the new flooring matches the old, and all “flows” from the original house to the new bit. Given the room size & concrete base, obvious option is to glue down the T&G. But - I have read about Elastilon and other makes of adhesive underlay, with some positive reviews on here. It claims to be easy once you get the hang of it, less messy, and flexes with the floor to accommodate natural expansion / contraction. Does anyone have experience of more than one type of this stuff, and have a preference for which is best? Never come across it before now. Also, I don’t see THAT many suppliers, which suggests it might not be as good as it is made out to be, if there aren’t many stockists....?? Grateful for any experience and recos. Thanks!