Newbie - double story wrap around extension Vs. single story and attic conversion?

[Notaclue]

Hi, I signed up to BH on the recommendation of my Dad who has just completed a rear extension and found the site incredibly useful.

 

I am in the process of moving into a 1930's (ish) semi which I am looking to extend and wanted some input on the ideas I have in order to get  the spaces I want to add without blowing the budget and before we engage with an architect.

 

I have attached a copy of the existing floor plans. The bay windows are to the front which faces east and main entry to the house is via the side. 

 

Downstairs I'd like to add a porch, boot room, WC and utility room (potentially via a side extension). I'd also like to combine the back two rooms with an extension to house kitchen/diner/living area. We have no restrictions to the rear as there is a very large garden, however, we only have 2.8m from the side of the house to the neighbours boundary (marked with a red line in my mock ups) and we'd like to retain rear access of approx 1m.

 

Upstairs I'd like to make the main bathroom larger and add a master bedroom with en-suite and walk in wardrobe to the rear. The two options we have considered here is a double story extension over the existing kitchen (upstairs image 1), or an attic conversion, with the stairs going through existing entry to bedrooms 3 (upstairs image 2).

 

I have attached some suggested plans but would love others input, as you experts may come up with something I’ve not considered. What are your thoughts? 

[larry]

Which side do you get the sun on? 

Bit of a loss of light in bedroom 3 and first floor stairs? Depends what your plans were with the new wall I suppose or roof. 

 

Consider whatever you can to upgrade thermal efficiency also. Including the old house. I'd be thinking also solar PV and whilst I've got easy access to floors etc MVHR. 

But I'm no architect! 

[twice round the block]

You state in the title Attic Conversion, then there is no mention.

 

Most people could build or do the bulk of the work themselves for a two storey extension, but loft conversions are very specialised and not a project for an amateur builder to take on.

[Notaclue]

@twice round the block I don’t have any plans of the attic but if we did this over a double story extension then ideally the stairs would run through bedroom 3 as per the last image. This would prevent losing light and aesthetics from the window on the current stairs from ground to first floor. 
 

we thought maybe an attic conversion maybe less costly than adding a double story extension. But I’m a complete novice in this field.

[Notaclue]

@larrythere would be no light lost in bedroom 3 as this room adjoins the neighbouring property. Potentially running the stairs to the attic through the back of this room, we thought would preserve light on the landing as we have a large window over the current ground-1st floor staircase. 
the front of the property faces east and the rear west. 
 

I’ve not got as far as thermal efficiency as yet. I want to get the basics of the layout/cost for build size and scope before we consider other details, but I’m keen to look into all of our options. 

[larry]

3 hours ago, Notaclue said:

@larrythere would be no light lost in bedroom 3 as this room adjoins the neighbouring property.

 

Ah OK, I wondered if it would it be potentially overshadowed by the extension?  ☺️ But if the neighbours are to the south and they don't have anything sticking out that makes sense 

 

3 hours ago, Notaclue said:

Potentially running the stairs to the attic through the back of this room, we thought would preserve light on the landing as we have a large window over the current ground-1st floor staircase. 

 

 

Don't quite understand this but can't completely get my head around your attic plans (me not you!)

 

3 hours ago, Notaclue said:

the front of the property faces east and the rear west. 
 

I’ve not got as far as thermal efficiency as yet. I want to get the basics of the layout/cost for build size and scope before we consider other details, but I’m keen to look into all of our options. 

 

Makes a big difference to planning even at an early stage, though. You'll want to think about heating and DHW and there no better time to get your pipework in the right place than when you're ripping much of the house apart. Ideal time to consider an ASHP also, put in bigger pipes, and possibly UFH or bigger rads. If you've got a combi boiler that means putting a UC in somewhere. 

Attic conversion would rely on conversion to a warm roof system  (presumably you've got felt and tiles presently).  What's height like in the loft? 

 

Easy to build the new stuff to existing thermal spec but that doesn't help much if rest of house is a leaky sieve. I guess suspended floors in original house if 1930s, so ideally you'd pull up  boards and get some insulation under (maintaing ventilation). Cavity walls? If so are they filled, cavity may be quite narrow so you might not get much insulation in there. So thermal PB as well on top? Or EWI? Again, makes sense to think about all this in the round as well be much easier with scaffolding already  up etc etc 

 

And a big message I've picked up from this forum is to pay attention to detailing for thermal efficiency airtightness etc which is basically about taking time on each bit, but that often means keeping an eye on trades who are just keen to get job done and signed off. 

 

Other thought, access to drains OK for your downstairs WC in that location.

 

Considered ICF?  

 

Random thoughts and defer to others' expertise 

[larry]

And If option 2, roof above blue square would be what? Top Needs to be below window for bedroom 3 

 

Is wall between existing dining and kitchen bearing any load?