Building control drawings for dormer extension.

[Del-inquent]

I'm looking for some examples of building control submissions for a dormer extension. 

The property (chalet bungalow) currently has a small (2.4m) dormer on one face of the roof, I'd like to extend it to about 90% of the width of the roof. I have significant design and drawing experience, but zero experience of the new part L and reading it is driving me slightly insane. 

[nod]

You can do it yourself 

But you will also need a structural engineer’s calcs 

probably as cheap to get him to do a drawing and submit it for you 

[ETC]

Can you post some pictures/sketches of what you want to do?

[DevilDamo]

In relation to extensions or alterations to existing dwellings, the amended ADL isn’t a whole lot different to the old ADL. Providing you know where to look, you’ll be fine. The main change is the reduction in u-values and the table is easy to follow.

[Del-inquent]

On 12/08/2023 at 19:32, ETC said:

Can you post some pictures/sketches of what you want to do?

They're very rough and basic at the moment as I can only get round there occasionally at the moment to work out dims, but in essence this is the plan.

As-is at the top, as intended at the bottom.

[Del-inquent]

@ETC does the above give enough info to form an opinion from or would you need to see more?

[Temp]

So I believe you want Section 10 on Page 61 "Section 10: New elements in existing dwellings, including extensions". More specifically paragraphs 10.7 to 10.11.

 

 

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Subsequent paragraphs give alternative ways to comply if you have issues with the above.

 

Table 4.2..

 

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I'm not 100% sure how to interpret section 10.7 d(i) in your case. It looks like there will be three windows serving three rooms in the dormer. I would work out the percentage for each room individually. They must each be <25%.  If not you have to do the more complicated calculations in the other parts of section 10. 

 

Paragraph 4.13 might also be helpful if you get stuck.

 

Edited August 19, 2023 by Temp

[Temp]

When you say you have design and drawing experience does that include structural engineering of roofs? eg Are you familiar with the different methods used to stop a roof pushing the walls out and the ridge sagging?   

 

 

 

 

 

[Del-inquent]

On 19/08/2023 at 13:41, Temp said:

When you say you have design and drawing experience does that include structural engineering of roofs? eg Are you familiar with the different methods used to stop a roof pushing the walls out and the ridge sagging?   

 

 

 

 

 

I've drawn them up from others specs, not done the calcs myself, I'd be getting some help on that front from a friend.

 

[Dave Jones]

On 12/08/2023 at 17:24, Del-inquent said:

I'm looking for some examples of building control submissions for a dormer extension. 

The property (chalet bungalow) currently has a small (2.4m) dormer on one face of the roof, I'd like to extend it to about 90% of the width of the roof. I have significant design and drawing experience, but zero experience of the new part L and reading it is driving me slightly insane. 

 

 

https://www.buildingregs4plans.co.uk/pre/loft_conversion_plans_new.php