Probably bitten off more than I can chew...

[Allthegearnoidea]

Hi All,

 

I'm glad to have stumbled upon this fantastic resource, as we've started a single-storey extension and I have a lot of questions!  Fingers crossed I'll be mostly OK once it's watertight, but everything up to that stage is all new to me.  After having some proposals done by an architect we know, we approached various builders for pricing and at that stage realised we would need to contract individual trades, do as much as possible ourselves, and have a lot of patience to be able to do this on our budget.  To date, the groundworks are complete (although, the drainage installer forgot the connection to the new W/C and is now having to dig up part of the slab) and walls are up.  I spent most of yesterday covering up the cavities to stop the insulation getting wet over what remains of the winter.

 

I'm waiting on advice from a structural engineer on building the roof, as the low pitch has made things a bit difficult and I have only millimeters to spare.  I'm currently struggling with making sure the drainage from the existing upstairs W/C is building regs compliant, and making myself very confused...thread pending.

 

I'm pretty good with AutoCAD and Google Sketchup, and being able to visualise things in CAD has been a real help.

 

 

 

 

[Thorfun]

Welcome! Best of luck with it. 

[markc]

Good morning and welcome, being able to visualise something is a big advantage. Loads of information available on here by searching past threads and blogs.

[kandgmitchell]

Can we presume you have approved drawings for this project. Did they show the wc connection? Isn't the roof construction shown on them?

[Allthegearnoidea]

 

9 hours ago, kandgmitchell said:

Can we presume you have approved drawings for this project. Did they show the wc connection? Isn't the roof construction shown on them?

 

Hi,

 

Yes, we have building control drawings all approved, they did show the WC connection but the groundworks guys missed it - I was in Scotland at the time doing my day job.  Bit of a pain but they are a good bunch and are fine to come back and sort it.

 

The roof design on the drawings is a bit vague and subject to structural calculations.  Happily we have a retired SE in the family and he is working with me on this.  I'm using Redline Mockbond tiles which will go down to 17.5deg which is really tight to the windows - plus, due to the design of the roof (no internal ceiling) it needs a skin of plywood to stiffen it which means double battening, bringing the height up again.  I think I'm going to get away with it by shaving the lower battens and having a larger than usual birdsmouth with a bit of reinforcement...approval (from SE) pending.

 

 

[Russdl]

22 minutes ago, Allthegearnoidea said:

I'm using Redline Mockbond tiles which will go down to 17.5deg which is really tight to the windows

Why not go for a flat roof, wouldn’t doing that solve your problem?
 

On 18/01/2026 at 16:39, Allthegearnoidea said:

do as much as possible ourselves

EPDM is very DIYable. 
 

 

 

[Allthegearnoidea]

8 minutes ago, Russdl said:

Why not go for a flat roof, wouldn’t doing that solve your problem?
 

EPDM is very DIYable. 
 

 

 

 

Well, in hindsight and all that...  If I'd known getting this part right would have been such an issue I might have done things differently.  BC have signed off the drawings now and the walls are up, so pitched roof it is.  I love EPDM, I've used it quite a bit before - but when it comes to the details such as sealing round rooflights, I can see that getting very fiddly.  Once the roof is framed I think I'll be enlisting a roofer for the tiles.

 

[Russdl]

41 minutes ago, Allthegearnoidea said:

but when it comes to the details such as sealing round rooflights

Do you need those? It’ll be plenty light enough in there with the windows you have planned, those roof lights will just add complexity and cost (and maybe leaks) and be noisy when it rains. 
 

Wracking my brain for a ‘positive’ but can’t come up with anything. 

[Allthegearnoidea]

5 minutes ago, Russdl said:

Do you need those? It’ll be plenty light enough in there with the windows you have planned, those roof lights will just add complexity and cost (and maybe leaks) and be noisy when it rains. 
 

Wracking my brain for a ‘positive’ but can’t come up with anything. 

 

I think it will make a difference, we have a lot of surrounding properties so need all the light we can get!