Tongue and groove floor boards?

Hi rugby I very much doubt this is to do with fire regs ! ( don't hold that against him ) But from experience I'd never lay pine to start with in a loft . For these reasons . To lay them straight only joints in you loft would be pretty awkward , it's one on the first jobs and speed is at essence at this point as the more hassle there is your in more danger of coming through ceilings or just damaging them . The other thing is in short by the time your lofts finished the boards will be dirty and probably damaged this will only give you cause to get on at the builder and weeks of sanding to get the damage out . Last thing is and this is a definite . When the plasterer does his part the moisture in the air will expand the pine floorboards . When they dry out they will shrink again causing you to be unhappy and also drafts . So this is what to do , carry on with your loft converter let him put chip board down and making sure he allows adds probably 18 mm to the rise on the stairs and making sure you make it clear your adding 18 mm to floor for doors ect , you could even ask him to leave skirting a off , then when the plaster is totally dry leave the flooring in the room unfitted ( to acclimatise and simply fit the flooring on top followed by skirtings , bingo everyone's happy . Don't forget chip board in a loft floor takes only a couple of hours to fit but floorboards done right take up to two days . So you will have to pay and this might be the real reason he's shy about putting it down . Thanks woody apex lofts Barnsley

A quick chat with your building inspector will clear this up(fire issues).I doubt you will save money using individual softwood planks anyway.If you builder has trade accounts he can probably get the chipboard for around £7 a sheet.It would cost less on labour to install as well.More than enough saving to pay for laminate flooring (which would also be better for sound insulation than stained floorboards alone).