Couple of comments - 1. Have you got sufficient air changes; 2. Has the building dried out; 3. As mentioned by Nige F PIR insulation material can give off some noxious fumes which are known to cause sensitivity in some individuals, may smell nice to some people but that does not guarantee you won't get sensitised, hence read the instructions! Regretfully, getting de-sensitised can be extremely difficult!!
You should have plenty of ventilation to dry the place out and remove any fumes/gases for at least a few weeks - its no good shutting doors and windows, which then trap the odours (fumes/gases) in the building. Assuming you have heating in the outhouse, one remedy to try would be to heat the building and basically 'burn the building in' 24/7 for say 3-4 weeks at around 28C. Raising the temperature in this way will encourage off-gasing of any suspect materials used in the construction of the building. Then reduce the temperature for normal day to day living, give the building a couple of more weeks to settle down and you should notice an improvement, can't say it would be 100% sucessful but it would be hoped that you would have no further problems.
4. The stuff you put on the floor can have similar properties to PIR insulation - you probably noticed the smell on the first couple of occassions on entering the outbuilding but paid it no attention, your sense of smell then adapted to the smell and further exposure caused sensitisation of the mucous membranes. The system you have used on the floor is probably moisture resistant, but is unlikely to be vapour resistant (I will stand corrected on this point) but I know from experience that to get a vapour resistant barrier on an existing concrete floor required 3 coats of a 2 pack expoxy resin, the company would not give a guarantee on a 1 coat system!
The only thing I can suggest is try out the remedy in item 3, and I hope you get the result you are looking for!
Regards
