How to install a door in a hallway with overhead ducting for aircon?

[ShamDaMan]

I'm looking to install a doorway to separate one bedroom area from the rest of the house's living areas and other bedrooms for privacy and sound insulation (older people at this end) but unfortunately I have the air con return duct located in the bedroom area side of the hallway (i.e. on the other side of the proposed new internal door). I still want to be able to run the air con after closing the door, but need the air to flow to the return duct. (see markup below).

I'm looking to install a doorway to separate one bedroom area from the rest of the house's living areas and other bedrooms for privacy and sound insulation (older people at this end) but unfortunately I have the air con return duct located in the bedroom area side of the hallway (i.e. on the other side of the proposed new internal door). I still want to be able to run the air con after closing the door, but need the air to flow to the return duct. (see markup below).

I THINK I'll be able to do this by installing the door as pictured, but somehow installing a "bulkhead" type structure to allow air to flow above the door to the return duct in the ceiling.

The issue is, the house is a steel frame house. I don't want to cause too much damage as when it comes to sell, it might need to be returned to original layout. How best to do this? I was thinking just some 2x4 framing to support some drywall lowered "ceilings"....(maybe with insulation of some kind to still provide noise insulation). The size of the oroginal return duct is 55 x 75 cm for a total area of 0.4125 sqm. If the "gap" above the proposed door is 45cm, the width of the new return duct would need to be .4125/0.45 = 0.91 m (or 91 cm), which is fine as the current width of the hallway is 100cm. I would install a return duct of say 45 * 95 or something above the door to allow the same volume of air to flow to the original duct).

Is this:

1. Is this feasible/Possible (will I be doing damage to the air-con unit at all - even though the flow will be able to be maintained?)

2. How best to support the new lowered ceiling height by tying into existing vertical steel frames through the existing drywall/gyprock?

Thanks in advance.

[EricL]

Hello @ShamDaMan 

Welcome to the Bunnings Workshop community. It's wonderful to have you join us, and thanks for sharing your question about installing a door in your hallway.

Let's start with the false ceiling, I suggest speaking to your air con manufacturer and finding out what kind of front clearance the return duct needs. If the gap you have is sufficient then it's ok to build the false ceiling. I propose not building anything yet not until you get the necessary information. 

The best way to support the ceiling is by building a lightweight frame to hold the gib. It will be necessary to locate the fixing points in your wall and ceiling so that its fully supported. You can either use a strong magnet or a stud finder to locate the steel frame. 

I suggest drawing up your plan in detail on paper or pc. By determining the amount of materials you'll need, you won't feel as lost. I then recommend doing a list of steps that will guide you on what needs doing first. 

Drilling into the steel frame is unavoidable, but by mounting only where it is necessary will reduce the amount of damage you need to do to your wall.  

Let me call on our experienced members @Dave-1, @TedBear and @homeinmelbourne for their recommendation.

If you have any other questions we can help with, please let us know.

Eric

[Dave-1]

Good Morning @ShamDaMan 

I do like the ability to close off areas for air  con and also from noise.

The door itself would be fairly easy to do with the spacer above (I have hung one door and yeah it took me awhile lol I said fairly easy meaning its possible) The Hallway is 1000mm width, Doors are from 720mm to 820mm depending on what you want. That gives you 140mm ish to play with. 

Two vertical pieces of timber with a rectangular box between them at the top, then faced with dress timber plus the 3mm ish gap around the door would work. Plaster the sides and above the door either side afterwards and it would look pretty nice.

With the concern over the aircon return. How about a new grill on the other side of the door and tapping the tube from that into the existing tube in the ceiling? You could hit up the air conditioning people and see if the air movements will be affected.

Dave

[JacobZ95]

Hi @ShamDaMan, 

Can you advise why you were planning on lowering the ceiling height?

I may be misunderstanding but I don't see a reason that you'd need to lower the ceiling height. Assuming the duct is running down the hallway towards you, could you not just move the return to the other side of the door?

Might not work for you but just a thought,

Jacob 

[ShamDaMan]

Hi Jacob the cost of moving the duct is probably more than just building a false ceiling. It's just for a granny flat for my mother. She doesn't like air con too cold for her so she'll not want the air for her side of the house. 

[EricL]

Hello @ShamDaMan 

Thanks for sharing that extra information about your false ceiling plans. 

Please keep us updated with your progress, we look forward to seeing the start of your ceiling frame.

If you need further assistance, please let us know.

Eric

[AlanM52]

Hi @ShamDaMan,

Without a sketch of the ducting layout in the area I am still thinking (pretty sure) the cost to move the return air vent would be lower and require less effort than building a false ceiling.

I am suggesting:

Relocating the return air box to the other side of the proposed doorway but before doing that check if the ducting will reach the new location - it should.

Remove the return air box and install in new location.

What about the grill?

Most likely you will use the existing grill and buy another one for the previous location and cover in some way - about $100.

Cheers

Cheers