Extending an existing dormer in all directions, plus insulating other parts of the chalet roof

[Del-inquent]

I'm looking at a potential project, a chalet bungalow. 

It's pretty small upstairs and whilst the front elevation has 2 dormers, the rear only has a single tiny dormer which seems daft, most others in the area have almost full width on the rear elevation. There is also room at the rear for a 1.5m extension for the full width.

I've done plenty of builds / renovations before, none of them have ever been a chalet so this is a new one to me. I'd love any advice full stop on potential pitfalls and problems, plus advice on how it would be best to extend the joists so that the majority of the original rear wall could be removed. I would not want a dropped steel below the joists as the ceilings aren't exactly high in the first place.

Also, I was thinking that it would be good to make better use of the existing eaves on the front elevation (which are inaccessible) by replacing the current wall with slide in storage between the posts. At the moment, the back of the existing wall is insulated so I'm thinking of putting insulation between the rafters instead - any pitfalls here to consider, or tips for best practice on doing that?
 

[Spreadsheetman]

My chalet also had 2 sloping roof dormers at the front in the bedrooms and a single small dormer at the rear which was the bathroom. It was extended in 2009 by building the entire back wall up and fitting a shallower pitch rear roof. This added full-height rooms across the entire rear of the house so an en-suite and a large walk-in wardrobe were added.

 

The revised roof was supported with a large beam just above ceiling joist level supported at the ends on the eves walls with a central vertical support steel (hidden in a stud wall) transferring some of the load down to an internal load-bearing wall.

 

I thought it was a very good solution to some of the inherent issues of the chalet upstairs layout.

 

I also have eaves with dead space at the front, but mine are quite small so not worth trying to create storage in there.

[Radian]

2 hours ago, Del-inquent said:

plus advice on how it would be best to extend the joists so that the majority of the original rear wall could be removed.

A SE designed UB to pick up the ends of existing joists and carry the new 1.5m lengths on the other side?

[Del-inquent]

On 11/12/2022 at 20:31, Radian said:

A SE designed UB to pick up the ends of existing joists and carry the new 1.5m lengths on the other side?

Yes that's what I assumed, I'm just thinking about supporting the beam, without it being intrusive in the rooms below. My brother is doing a project at the moment and they've made him have 600mm pillars to put the beam on - last project I did it was 300mm required for a longer beam. Not sure if that's because something has changed regulation wise or just his SE being overly cautious!

[Del-inquent]

On 11/12/2022 at 19:48, Spreadsheetman said:

My chalet also had 2 sloping roof dormers at the front in the bedrooms and a single small dormer at the rear which was the bathroom. It was extended in 2009 by building the entire back wall up and fitting a shallower pitch rear roof. This added full-height rooms across the entire rear of the house so an en-suite and a large walk-in wardrobe were added.

 

The revised roof was supported with a large beam just above ceiling joist level supported at the ends on the eves walls with a central vertical support steel (hidden in a stud wall) transferring some of the load down to an internal load-bearing wall.

 

I thought it was a very good solution to some of the inherent issues of the chalet upstairs layout.

 

I also have eaves with dead space at the front, but mine are quite small so not worth trying to create storage in there.

I'm trying to visualise how yours was done, failing a bit lol. 

I don't think any of the internal walls on this place are load bearing, they don't appear to be. There is however *one* position beside the stairs, about 1m off centre of the ridge that I could run a steel down all the way from ridge to ground floor, will have to have a look and see if a foot could be put down there.

 

[Radian]

You might be able to get the SE to spec. a goalpost arrangement - we have a 6m UB supported at each end on a 100x100 square hollow section post. This hides in the inner leaf and is strapped to the blockwork courses. It has to have a good connection to the foundation though.