Around the 1500’s the less wealthy people of this land shall we say had only dirt floors in their homes, hence where the saying “Dirt Poor” came about. However the more well off homeowner would have covered their floors with Slate or Flag Stones, which seemed to be a good idea at the time but became dangerous and slippery when wet.
So to stop slipping on these floors “Thresh” another word for Straw, was spread over the floor. However with straw being light it would blow away because the gap between the bottom of the door and floor level was such that the wind just blew the Thresh (Straw) in.
So to prevent this a strip of timber was placed on the floor covering the gap creating the “THRESH HOLD”
Thresholds are probably one of the most important function in today’s manufacture of Composite doors, without one the door would have no draught barrier at the bottom of the door, also rain water would penetrate in ruining carpets wood laminates and the like.
Choosing the correct Threshold is important, Part M Mobility Threshold (Low Aluminium) for instance would be required for Wheelchair users ease of access or for those people that find it difficult to raise their legs when stepping into their homes , putting a high Threshold in would hinder Wheelchair users access.
You would not be able to put a low Ali Threshold on an inward opening Composite door for example if the internal floor level is higher than the Threshold as the door simply would not open.
To overcome this type of issue a higher “FULL FRAME UPVC THRESHOLD” would be recommended.
If you are unsure which Threshold would be best for you when buying your Composite Door you should always seek professional advice because if the door is manufactured with the wrong type of Threshold it will be an expensive mistake to make as the door would be rendered useless as these cannot be rectified once manufactured.