Old buildings with original decoration inside and out

For old buildings used as museums with minimum renovation, to respect historic interiors, much less strict rules apply:

The roof must keep the rain out.

Direct sunlight may not reach any object.

Artifacts must be placed a minimum of 10 cm away from walls which are likely to reach a surface temperature more than five degrees from the air temperature in the middle of the room.

The temperature should be reduced in winter so the RH does not fall below 25%.

The requirement for environmental measurement and recording applies to old buildings. Indeed it is more important to know the performance of an old building.