Raising a threshold for bifold doors

[Ashworth1]

I have put an extension on the back of my house. When I did the extension I left the block work below the bi folds 50 mm lower than my internal floor level. The threshold for the bifold doors are 75 mm so I have 25 to play with. I now have changed my mind to the flooring I want- so I need the threshold to be 20 mm higher. Any idea how I can do this? Many thanks

 

[Gazman16]

Is there a 20mm gap above the doors to take them out and refit them? If not your pretty much screwed I'm afraid.
Do the doors open out? if so you could ramp down to the threshold with a bit of timber or a tile edging trim

 

[Ashworth1]

Hi. Thanks for the response . I should have explained- the bi folds are not fitted/ordered yet . Just need a way to raise the threshold 10-20 mm? Don't want to start knocking brick work out ect .

 

[Nabbers]

Just order them smaller in height. Sounds like you figured that bit out, so the problem is the gap it will leave?

You would just pack them up and fill the gap with cement or even foam and then render over.