Sealing existing floorboards

[Jim Miller Design Ltd]

An age old problem, but what is the best way to seal square edge timber floor boards after floor sanding (without the disruption of taking the floor up or working from below)?  Is there a cleaver solution with black self adhesive expanding foam tape such as
http://www.lynvale.co.uk/?gclid=CJOx4syR0Z8CFZEA4wod0jLpJw

[J Ingram]

Not very green , but I've seen people using the boggers friend gripfill the some sanded dust on top

On parque they use the sanded dust mixed in with a clear resin glue or laquer for corking the small gaps

perhaps something similiar or dust mixed with linseed oil ? would need to be flexable and expand and contract with the boards .

[Jim Miller Design Ltd]

Looking into this, using expanding foam tape such as Compriband 600 (which is used for sealing gaps around windows to improve airtightness) might be a good solution.  It comes in various widths to suit the gap, expands to fill the gap with one face sticking to the floorboard, stays flexible for years and being black is barely noticeable.  I've tried a sample and it looks good so far.  Its not cheap at about £10/m2 but the benefits in terms of improved thermal performance and comfort must make it worthwhile...

[J Ingram]

Sound like a tricky job to get the stuff in , probably quicker lifting the floor and doing it properly
http://www.fensterversand.com/illbruck-illmod-60015-p-479.html have a look here for a cheaper foam tape.
arh just realise you put m2. similiar then

[Andy Simmonds]

is expanded compriband type tape actually airtight (open pored foam structure?) - presumably is not a vapour check?

[Nick Grant]

Airtight if compressed enough but might cost more than the floor!