Closing off Vaulted Ceilings

[mike2016]

I am planning to close off the vaulted ceilings in the upstairs bedrooms (new timber frame build) at the 2.4m height. One room is 3.4 wide and will need 12 x 175 x 44 joists, the other is 4 meters wide and needs 5 x 225 x 44 joists. The first room is fine but it's the second with the longer span that the joist height squeezes any useful storage space as it has an ensuite blocking some of the available space to contend with. I was hoping Pozi Joists, i-joists or Glulam would be available to reduce the height of the joists a bit but they are all 200mm deep at a minimum. I could reduce the joist depth to 200 or less but for that span if someone does put a load of books up there the deflection could cause issues / be unsafe. I could try splitting the span with a joist at 90 degree midway but there's only 2x4 stud at one side to support this whereas the other is structural. 

 

Question is - can I get away with a smaller joist if it's not habitable, storage only and to support a person crawling around? No water tank etc. Or just state NO storage here please and have limited flooring to discourage it. Might fit a Xmas tree but that's it! 

 

The other question is I plan to use a ledger board at either side with joist hangers, are there any good guides / specs for this & nails etc online? I could get an SE but it's a bit overkill for the use it will be put to. Open to advice on this though. Thanks! 

[JohnMo]

I deliberately went completely the opposite way, our original drawings had flat ceiling had the architect change to vaulted. Every room feels roomy and airy, would not go your direction.

 

What is the motivation? Seems a lot of work to possibly store stuff, you will not use or see until you move house.

Edited August 7 by JohnMo

[Conor]

If this is purely for storage reasons, a shed would be cheaper and more practical. We love our high ceiling and would hate the idea of them being so low.

[mike2016]

Thought it would be echo'y and while I have a shed storage is always handy. Also I've to fit a MVHR system up there - the ducting will be going out the gable end in the left room with the unit situated in the "hot press" on the landing. Big 210mm pipes. I can box these out a bit but have to keep 2.5m separation when they exit the building if possible - off the left hand side. There is a major road 2 meters off to the right of the house blocking that path. 

Worth considering though, will have to have a think about the ductwork.....

[JohnMo]

10 minutes ago, mike2016 said:

Big 210mm pipes. I can box these out a bit but have to keep 2.5m separation

To need 210mm pipes your house must be huge?

 

Use a directional terminal on the wall, these have the inlet and outlet pipes next to each other. Zero separation required.

 

Use coanda supply nozzles, these can be situated anywhere in a room near the ceiling and air follows the ceiling for quite a few meters before coming down.

 

So assuming you have the unit in the landing cupboard and ensuite ceiling is flat. Bed 3 duct would go over ensuite and out of the wall, bed 2 could have the supply nozzle above the door.

Edited August 7 by JohnMo

[Conor]

This is our master bedroom. We put in a ceiling 200mm below the ridge beam to allow for services. Still gives us 3m ceilings.

[mike2016]

One problem is the neighbour fitting a wood burning stove and the chimney is closest to the ensuite, was hoping to place the intake closer to the front of the house where the prevailing wind would better clear any smoke from entering the system if it gets blown down the side passage between the two houses. Also have to fit two manifolds somewhere or push the MVHR unit downstairs. That 210mm is the insulated pipe diameter, it's smaller inside. 

Will have a look around the space later and make a decision. Will probably put joists in Bed 2 as it's only meant to be used as an office and not rented out (unless I blow my Budget!) and that will give me storage. As for Bed 3, full ceiling gives me the most options with ducting, it's always push here and it sticks out there with houses isn't it?!! I like the idea of the mid ceiling though but the intake would be obvious that way unless I bury it in the wall somewhere, ah decisions, decisions!! 

[ProDave]

We have a frght mixture of upstairs ceiling heights.  The whole roof structure is hung from ridge beams so all rooms could be vaulted right to the ridge if wanted.  But we only did that with one room, which has a mezanine above the adjoining small bedroom.

 

Landing and bathroom we did a normal 2.4 metre ceiling to give us a just about standing headroom bit of loft space.  And the master bedroom we did with a 3M ceiling height still giving us a feeling of most of the available height, while giving a further bit of crawling height loft space access via a step up from the main loft.

 

If you want smaller joists to preserve headroom why not fit more of them at 400mm centres or even closer?  At 400mm centres I used just 12mm OSB as the loft flooring to preserve headroom.

[mike2016]

The 400mm centers is an option, just need one set wider at 600mm wouldn't I to make it possible to get up there after a turkey dinner at Xmas?! Or possibly access it from a hatch in the landing?

 

Was using first floor spanning tables but switched to attic tables today and found with c24 I can do 44x175 in Bed 3 and 44x150 in Bed 2 which is much better. Just a bit harder to get hold of. 

[ProDave]

At 400mm centres you frame around the opening probably needing doubles on at least one side of the opening.

 

Regarding C16 vs C24, I was building my decking frame recently and accidentally found if I ordered 6 metre lengths they were all C24

[mike2016]

One last question - do I just fix a length of wood at either end into the timber frame and hang the joists off that using joist hangers? Was just going to use 92mm nailgun nails through the 44mm wide timber into the TF structure but can't find any details on NHBC to see if this is sufficient? Thanks. 

[JohnMo]

5 minutes ago, mike2016 said:

do I just fix a length of wood at either end into the timber frame and hang the joists off that using joist hangers

You should design it, ideally with a structural engineer input.

[mike2016]

Thanks - you should see what the SE did with my brise soleil but I'll check in with the timber frame supplier and see what they think. It will only be used for services (MVHR ducts,electrical wiring) and some storage. 

[Kelvin]

Our roof structure is also hung off the ridge beam. We vaulted the ceiling in the open plan upstairs sitting room and coombed it in the bedroom. It’s 2.9m high to the ridge beam in the vaulted bit and 2.7m to the flat ceiling of the bedroom. We also removed all the voids on one elevation. Transformed the upstairs from small and tight to roomy and airy.