Chalet Bungalow Extension

w4terfall

Hi guys, super long post but tried to give you all the info. 

We are at the very start of planning out what we want to do to a house we are purchasing. 

It’s a 1960 semi chalet bungalow. Around 120m2. I believe the side building to be original. 

Having looked through what is available through pd and the neighbour consultation scheme we would be hoping to put a single storey extension right the way across the rear of the property. 

With no certain figures at the moment due to lockdown it would end up being roughly 10 x 5m. There is a step back to the side portion of the house so unsure wether we would need to replicate the 2m step. This would mean it being 7x5 and then 3x5.

We are hoping that the space would become a lounge in the centre with bifolds and the 4th bedroom to the side that is stepped, with a new master being made also to the other side. (A split of 3/4/3m minus wall thickness) So no bathroom or kitchen to be incorporated as they are staying put.

Due to the current roof pitch I would imagine a flat roof height of 2.3m externally and 2.1 internally with a lantern in the centre of the lounge.

We would be almost on the boundary line of each neighbour. 

There are no rear man holes to contend with as they are all on the front of the property. Only a rain water drain on the corner of the property. 

A few things to ask. 

Firstly I guess is, does it look feasible or am I looking through rose tinted specs at what I would like to happen. 

What is judged as being the best construction for the walls of this type of structure currently? (Knowing a builder makes me want to stay with block and render, but is that still the cheaper option or is timber frame taking over)? 

We are in Essex. The m2 prices seem to be all over the place and understandable however we are not flamboyant in desires and pretty much like plane white walls with a bit of colour splashed about the place. Are we really looking at £2k a m2 for a finished box essentially. If so how much would people estimate to get to a wether proof shell with 1st fix in place? 

Any advice appreciated, good or bad. Thanks a lot for sticking with the post, Pete

DOH_a

The feasibility is hard to advise on as we don’t know the housing market. Working on the rates you provided, you’d have approx. build costs. Are there other similar bungalows that have had these works done and are seeing the return for their investment?

Most traditional builders will opt for traditional construction, i.e. cavity block walls and render. There is the added speed with timber but there are also additional design details with timber to consider, e.g. sole plate details being raised off the ground, sizing and centres of studs as well as any potential walls needed for load bearing situations where you’d be restricted with timber beams and/or flitch beams as opposed to steel beams.

With my clients, I advise on a rate of £2k per sq.m (£200 per sq.ft) for a watertight first fix shell. It’s when people start talking about kitchens, bathrooms, bi-folds, lanterns, etc... is when these costs start to escalate. But also, builders I work with, their rates range from £1,750 up to £3,250 per sq.m. It’s also relative to the size of the project where the bigger the area, the more reasonable the rates are.

To advise you on the PD side of things, you would not be able to extend across the ‘whole’ width which includes the part set back. Reason being is that infill part would create an ‘L’ shape extension of which the PD rules for both rear and side extensions come into play. The rules for side extensions restrict the width to half the width of the house, which your
proposals would not. You’d be able to extend out the back (of the main rear wall) and then extend out the side (behind the set back part) but would not be able to link them together.

Another thing to think about that may apply is the new eaves of the extension should not be higher than original. With a flat roof extension, the eaves will be higher than the original house eaves, as you’d more than likely want to retain the internal floor to ceiling height? However, it appears the rear dormer may help you in that respect as in theory, you would not exceed the height of those eaves. If the eaves does become an issue, you may be able to get away with a pitched/gable roof with the triangular part of the roof facing the garden?

w4terfall

DOH.a said:

The feasibility is hard to advise on as we don’t know the housing market. Working on the rates you provided, you’d have approx. build costs. Are there other similar bungalows that have had these works done and are seeing the return for their investment?

There are 8 bungalows that are identical. Just slightly different plot sizes. One has had a completely new two bed built next to it on its land and sold on. Another has had a large garage and utility added and some of the others have had internal changes upstairs with bigger dormers to the rear. So alterations are being made but not like we are intending. I think a lot of the residence have older children so don’t need the space we do. 

Most traditional builders will opt for traditional construction, i.e. cavity block walls and render. There is the added speed with timber but there are also additional design details with timber to consider, e.g. sole plate details being raised off the ground, sizing and centres of studs as well as any potential walls needed for load bearing situations where you’d be restricted with timber beams and/or flitch beams as opposed to steel beams.

I feel more comfortable with block construction. Understanding it a little more I guess and having helped out with projects over the years. 

With my clients, I advise on a rate of £2k per sq.m (£200 per sq.ft) for a watertight first fix shell. It’s when people start talking about kitchens, bathrooms, bi-folds, lanterns, etc... is when these costs start to escalate. But also, builders I work with, their rates range from £1,750 up to £3,250 per sq.m. It’s also relative to the size of the project where the bigger the area, the more reasonable the rates are.

Thats good to know. The bathroom is brand new and the kitchen is on the radar for a different time frame to this build. So would just be plumbing for heating. 

To advise you on the PD side of things, you would not be able to extend across the ‘whole’ width which includes the part set back. Reason being is that infill part would create an ‘L’ shape extension of which the PD rules for both rear and side extensions come into play. The rules for side extensions restrict the width to half the width of the house, which your
proposals would not. You’d be able to extend out the back (of the main rear wall) and then extend out the side (behind the set back part) but would not be able to link them together.

I thought this may be the case hence the mention of stepping back that side so it was it was the same additional size just a different starting point. However the values does measure nearly 12m across and it would only be a 3m side extension so does that make any difference? 

Another thing to think about that may apply is the new eaves of the extension should not be higher than original. With a flat roof extension, the eaves will be higher than the original house eaves, as you’d more than likely want to retain the internal floor to ceiling height? However, it appears the rear dormer may help you in that respect as in theory, you would not exceed the height of those eaves. If the eaves does become an issue, you may be able to get away with a pitched/gable roof with the triangular part of the roof facing the garden?

For the roof line I worked on the height of the side building which is 2.3m high and 2.1m internally. This measures just under the bottom tile of the roof on the rear. Would this be suitable? Im
 it sure how the flat roof constructions need to account for water run off etc

Thanks a lot Pete 

DOH_a

You could look to approach a local agent and put forward your thoughts and build costs to see if they think they appear viable? The only real increase is when people starting adding bedrooms but even then, in some locations, the road or area will have an upper re-sale value.

If you stepped the side part back, will the projecting rear extension still be connected or linked to the projecting side extension? If so, this would not be classed as PD. As mentioned, you can extend out the rear and extend out the side but not infill the corner to link them. Have a look here... https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/190910_Tech_Guide_for_publishing.pdf (From Page 26)

The side building looks to be garage so the internal ceiling would traditionally be lower and the roof would not be insulated hence the roof build up equates to no more than 200mm. For your extension, I’d assume you’d want the new internal floor to ceiling to match that of the existing house, which may be around 2.4m? If so and based on that, the top of your flat roof could be in the region of 2.7m, which assumes a warm roof construction and is more commonly used where you have lanterns/rooflights. So your eaves would be higher than those ground floor elements meaning PD may not be an option. But as I mentioned, you may be able to argue and use the first floor dormer eaves as your maximum height.

w4terfall

Thank you for all the Info. Makes perfect sense. 

Elsewhere, someone has mentioned the neighbours right to light so potentially we can’t extend fully the opposite way either. 

DOH_a

Outlook, privacy and daylight would only be reviewed upon the submission of formal Planning application where the LPA can cross-reference and assess against Planning policies. If you do choose to explore your options via PD, then policies wouldn’t come into it. However and that being said, the Prior Approval route (with Neighbour Consultation Scheme) could take the outlook, privacy and daylight into consideration should the potentially impacted neighbours comment or object.

w4terfall

Ok so In your opinion what would be the best way to proceed. 

Speak to the neighbour informally and see how they feel about it.
 Then get some form of plan drawn? 

Or get what we want to build on paper and present it to them so they can see exactly what we would like to go with at risk of having to redo plans. 

Or not consult at all until the scheme called for it? 

DOH_a

Are you therefore thinking you can’t get what you want under PD so will go down the formal route?

It’s always advisable but not essential to speak to neighbours prior to an application being submitted. Neighbours would have a better understanding with drawings but don’t let their opinion (should it be negative) put you off. At the end of the day, the Planning Officer will make the overall decision irrespective if neighbours support or object to the proposals as approvals stay with the property and not the person.

w4terfall

For what we want, PD would be fine providing the neighbours were ok with it. 

Equally if they weren’t and we had to change the plans to have it only through the centre of the garden. Just a lounge would give us the living space we require.

We were purely trying to future proof for when the kids start to out grow their rooms by adding another space at the same time.