The bedroom door frames in my HDB resale flat needs to be lowered by about 3 inches due to running aircon trunking through my mbr door opening. The previous metal door frame has been already removed and the opening plastered.

Can anyone advice how can I lower the door opening? My ID suggested using gypsum board 'box-up'. I am afraid that it might not be 'solid' enough. Are they any better ways? Thanks.

The bedroom door frames in my HDB resale flat needs to be lowered by about 3 inches due to running aircon trunking through my mbr door opening. The previous metal door frame has been already removed and the opening plastered.

Can anyone advice how can I lower the door opening? My ID suggested using gypsum board 'box-up'. I am afraid that it might not be 'solid' enough. Are they any better ways? Thanks.

I have installed 2 out of 4 aircons with their thick trunking running above the door and there is no need to lower the door frame. How come yours have problem? Can you mount the fan coil unit on beams or higher than door frame to avoid this issue?

This picture shows the fan coil unit resting on the beam & I asked the aircon installer to construct additional 'dummy' trunking along the lower portion to 'blend' with the beam. So, at a glance, you may thought the fan coil unit is resting on beam completely.

The problem is that the beams in my flat are very low. They go down all the way to the top of the door opening. i.e. no gap at all between bottom of beam and door opening. These beams run between the walls of all 3 bedrooms. Dunno why hdb design like that...

This is not the case in my parent's flat as there is a gap between the beam and door openings so trunking can pass through easily.

If I dun do trunking this way then have to do a lot more trunking by running them around almost the entire lower perimeter of one of my bedroom

gypsum board on the door frame is out of the question.

They are flimsy and you will soon see crack.

The door fame is commonly made of solid wood, which expand and contract under different temperature with plaster.

Further more each time you close the door there will be vibration to the frame. i suggest you get them to use hollow brick or solid wood.

S$0.02

If HDB permits the usage of hollow block, I think u should consider it.

How much should I expect to be paying for hollow block or solid wood? My ID says they will be expensive. How about using plywood and covering the exposed area with gypsum board? Will it work well?

Hollow block worth nothing and its more towards labor cost you will be paying.

I recall one whole set of solid wood frame cost around $80, why not you get the frame maker to extend the top part.

ID and main con find all sort of excuse to squeeze $$$