You can also use underfloor heating in suspended floors and there are several ways of going about this.
One option is to insulate between the joists to prevent heat loss, and then lay a subfloor over the joists. The underfloor heating pipes lie on top of this, between battens. To ensure that the heat is evenly distributed, you can either fill the gaps with a weak sand/cement mix, or fit aluminium plates to the pipes to dissipate the heat evenly through the floor. The floorboards would then sit on top of this, held by the battens.
The timber must be really dry - if it isn't, it may shrink and crack with the heat. The moisture content of timber used in a wooden floor with underfloor heating should be about 8% for retrofitting and 10% for a new build. Alternatively, lay it loose for the first year, so that adjustments can be made for any movement. The surface temperature shouldn't go above about 30° or the timber may distort, and you should leave a gap around the edge of the timber floor to allow for expansion.