Structural timber joist or not

[Murch]

Hello folks. 1st time poster so forgive me if my terminology isn’t correct on certain components . Basically we have bought a new home to which we need to carry out certain renovations. The first job on the agenda is seeing if I can raise the height of 2 doorways. The older part of the house was originally a block of three very small cottages so also originally were not linked by doors between . I shall try and post a picture below for reference as I try to describe the issue . As the cottages we’re fairly small the upper floors are I think what is referred to as “vaulted” . Inside each room is actually a decent head height. However where they had put doors adjoining each cottage, the height of the doorways is some 5’! I’m 6’6” so don’t wish to bang my shoulders let alone my head ! The reason these doors are low is because there is a timber joist spanning each wall and tied to the outer walls with a bracket . So my 1st question is .. is this actually a structural joist even though “collar ties” are installed onto every rafter ? From the picture I shall attach the dividing walls do not extend to the point of the roof. Also there is no ridge board or beam, just rafter to rafter . 

[SteamyTea]

Generally, if a solid walls goes from the foundation to the roof, it is structural.

It can be removed and parts replaced with structural beams, but it needs to be properly calculated by a structural engineer who knows what they are doing, as it can impact on other parts of the building structure.

 

We have a good structural engineer on here, @Gus Potter, so hopefully he will come along at give some words of wisdom.

 

[ProDave]

I suspect those walls are supporting the roof purlins at either side.  So treat them as structural.

 

The only way to get enough headroom for taller doors, is move them towards the centre a bit.  The headroom at the edge is what made them put small doors there.

[ETC]

Move the door!