Extension idea and roof height issues

[kingandy2nd]

Hello all,

This our current project house

View media item 50058
It's ugly I know, but it has potential. Our plan, once it existing insides are renovated, is to build a double storey extension but demolishing the existing garage and build in its location a double garage with kitchen behind it, with to bedrooms above that.

The footprint of the existing house is approx 9 x 5.5m (w x d) excluding the garage. I realise I'll likely need to set back the extension, so was thinking an 6 x 8m extension.

One of the challenges of the design will get getting a decent roof design as I don't want a flat roof, however the existing roof has a really low pitch.

The existing roof rafters are only spanning 5.5m so in order to keep below the existing roof heigh that would be the maximum size I could use in the extension (I was thinking that these rafters would be turned at 90 degrees to the existing roof and connected to it by a hip), as I can't go for a much shallower roof angle anyway.

My idea was that the roof at the front should meet with the existing roof line, ie have the roof ridge towards the front of the extension, but then at the rear of the extension I would have the roof extended downwards as the same angle to below the existing roof line. I appreciate that it'll mean that a bit off room height is lost in the rear bedroom but at least it allows me to keep a pitched roof.

Does that seem a sensible idea or is there a much better solution that I've overlooked?

Thanks

 

[kingandy2nd]

Just for info, someone further down the road with the same house has built a similar double storey extension, however they have only built a single room depth rather that going nearly the full depth of the property as we would like to.

Plan can be found here to give an idea of how ours will look from the front, except I want a double garage on th ground floor.

http://forms.sefton.gov.uk/planning/2011/S_2011_1303_Plans_Existing_and_Proposed_Plans_(01).pdf

 

[jblack]

Could you build the new roof at the same profile as the existing with a valley where the two meet? Like an inverted 'W'.

 

[kingandy2nd]

thanks jblack, had thought of that one but it would make the house look a bit odd we though.

 

[luisdesign]

If you are looking to do a full length extension, as opposed to a half depth one like the house nearby, then you will not be able to mimic their roof design without introducing a crown roof. Otherwise you will probably find that the pitch is simply too shallow and end be being classified as a flat roof anyway.

Other options could include a shallow monopitch - which could either form a valley with the existing roof, or be pitched the other way. Depending on the orientation of the house this may offer more opportunity for high level windows for extra light if needed.

Of course, the exact design could set the roof above or below your existing roof line...

Ultimately though, you need to get your house drawn up, including all existing heights and then a designer can get to work implementing your brief. Once a building is drawn up it is much easier to manipulate the potential ideas and get an idea of more detailed restrictions / opportunities.

Do you plan on using a designer (or draftsman, technician or architect etc) or are you looking to get the design work and plans done yourself?

 

[kingandy2nd]

Thanks for you contribution luis.

Forgive my lack of knowledge, and unreliable google results, but is a crown roof a roof with a pitch to the sides and a flat bit on top?

We'll get the plans drawn out by a professional, but I would really like to have a idea of what I want in my mind before getting the professional in, as I fear that having to do several iterations might become quite costly.

 

[luisdesign]

Yes, that's right a crown roof has visible pitches but a flat section at the top. Sometimes this is necessary when you are matching an existing pitch line.

Another option as mentioned would be a monopitch next to the double pitch roof of the original house. think:

" / /\ "


or

" \/\ "


Of course, if you are not sure exactly how you want the roof to look, then you can just let your designer know and allow them to come up with some solutions!

I like taking detailed briefs from clients as it makes designing easy, but often in the course of drawing up plans I find ways of making things look or work better and will present alternative ideas to the client for their consideration.

 

[kingandy2nd]

Thanks again Luis.

I'm not sure if the //\ or \/\ style of design would be acceptable to planners as the house sit as an angle to the road so that side of the property is quite visible from the road.

On re-measuring I now think the original roof is actually 6m wide, so perhaps I would be better to reduce my plans slightly to have a 7m deep extension at the first floor level with a roof that drops below the original roofline by 50cm from and back to maintain the roof slope. That would still leave a floor space upstairs of 6x7m which is plenty to fit 2 bedrooms and an ensuite in I think.

Downstairs I'd still want the extension to be 8m (or possibly 8.5m) deep as I think the garage needs to be at least 5.5m deep so that leaves 2.5 (or 3) x 6m space for a kitchen. That would mean a small additional pitched roof at the rear of the extension at first floor level, and an extra rsj holding up the first floor rear wall but I think that might work out nicely if I can bung in a couple of velux windows into the additional roof to add extra light into the kitchen.

 

[luisdesign]

Being visible is not necessarily a reason to prevent design of that type. Some councils will look for additions which include roof elements to appear "subservient" to the main roof. This can be achieved in multiple ways - a simple way is to make the new roof step down from the original. However, you can still achieve a subservient roof appearance with a "/ /\" roof form... such as by setting the entire roof slightly lower and stepping it back slightly from the main frontage to that is appears smaller. Again, your designer should be able to come up with various solutions so I wouldn't get too worked up about working it out now.

You may want to have a look at guidance from your local authority. Most will have "design guides" which will give tips to householders about practices they encourage.

That's not to say you HAVE to stick to that guidance, unlike policy, guidance can't be bent and sometimes broken if the case for it is strong enough.

It's also well worth going and speaking with a planning duty officer about your ideas and any limitations. Some councils will only want to see you once youhave some plans, others are happy to speak with people informally without them... Check out the local authority website, as some councils will charge for pre-app advice whilst others will offer it free to eeryone, or free to householders but not companies.

What you want to make sure you have is decided what you need to achieve inside. As per my previous message, what you want to do is make alist of the things that you really want, and maybe even a list of things that you'd like is possible but not essential. You do not even need to think too much about WHERE you want those things exactly... a good designer should be able to work out the best solution and should be willing and open to talking ideas through with you.

The thing I find with people is that they often come saying (for example) "i want a big rear extension to my kitchen to make it bigger", when really what they want is more space for entertaining guests and by re-arranging the internal layout and exactly where certain rooms are you can make a much better space than if you were to simply add an extension!

 

[kingandy2nd]

Thanks again Luis.

Yeah, I am wary of doing anything with a roof design that strays away from the normal type of roof arrangement as I think given the bog standard design of any of the house in the surrounding area that it'll get knocked back.

My local council in sefton offer free householder pre-application advice, but as part of the requirement of the applications is that they need:

•Site location plan at an appropriate scale, usually 1:1250 or 1:2500
•Details of the nature and scale of the development proposed. More information may be required if more detailed advice is requested
•Sketch drawings of the proposed development to include a proposed layout, floor plans and elevations, sufficient to indicate the scale and height of development proposed.

From reading the above it would seem that I would have to have plans drawn up before doing the pre-application process, and if the design is deemed unsatisfactory I'd end up having to pay for two sets of drawings anyway.

Our council does have a list of approved designers that can have applications fast-tracked because they have proved that they are familiar with all the local council guidelines, but the problem is that there is only one such designer approved at the moment so I guess they have an ability to charge a premium because there is no competition.

 

[luisdesign]

I work by allowing complete freedom for clients to choose elements of work, so if someone just wanted a survey and existing plans then that would be fine...

Maybe you can just get "existing plans" drawn up by a designer in the first instance, then you can print out a bunch of copies of these and draw all over them to discuss your ideas with the planning officer... then you can re-approach the designer and appoint them to draw up proposed plans with the comments you got from the planning officer.

This way you may be able to break up the costs of the design work and avoid paying for the same thing twice.

 

[tony1851]

Our council does have a list of approved designers that can have applications fast-tracked because they have proved that they are familiar with all the local council guidelines, but the problem is that there is only one such designer approved at the moment .

Is that legal???

 

[kingandy2nd]

Our council does have a list of approved designers that can have applications fast-tracked because they have proved that they are familiar with all the local council guidelines, but the problem is that there is only one such designer approved at the moment .

Is that legal???

Bottom leftt hand corner of the web page they state they're the only ones, which was correct when I last looked a few weeks back

http://www.theplancentre.co.uk/

Although since I last looked they have added a couple of extra agents to the councils website

 

[freddiemercurystwin]

Frankly you sound like a bit of a nightmare client tbh, you're overcomplicating the whole design process.

Appoint a decent designer, who'll come up with a good design that looks good, meets Local Plan guidance and a has good layout.

I've only ever done pre-apps for front extensions.

It annoys me, people will think nothing of paying £800 or so to a solicitor for 5 hours work or £80K on an extension yet will baulk at paying a designer to come up with a decent design for their house. Why anyone would care about using a designer who may get an approval in 7 weeks rather than 8 is another mystery.

 

[kingandy2nd]

So you prefer clueless clients then freddy??

I have no issue with paying a designer, or any tradesman or professional, a fair price for a job.

But at the same time I would like to have a good picture in my mind of what this extension should look like beforehand so to be able to approach a designer with a creditable idea of what I would like the extension to look like in a way that is more likely to get approval.

Im sure you've come across good and bad designers in your time. i have no experience if using a designer so dont know which sort i might get, so in my eyes to approach them with a plausible outline would increase the chances of coming out with a design that's right first time for planning, but also something I will be happy to look at for the next decade!

Apologies if my desire to seek ideas and feedback here has irked you somewhat, but I thought the purpose of this section was for joe public to get assistance with such matters.

Regards
Andy