Query re double height extension

whatisayis

Hi and hope someone can clarify a few issues regarding the 40sqm planning exemption for a single house extension.

The house is an old cottage on an acre so there are no issues with boundary restrictions as there is more than 40m to the nearest boundary and much further to the nearest house. My questions:

Are there restrictions regarding length and width e.g. can you build 4m x 10m?

Would it be possible to build a double height extension e.g. 20sqm room upstairs and another 20sqm room downstairs without the need for permission?

The original walls of the cottage are nearly 60cm thick so we were thinking of connecting to the old house by constructing a closed in walkway of approx 3sqm from the original back door to what would be effectively a new building. Would this mean that we could disregard the depth of the original walls, which would not be directly connected to the new build, and just deduct the 3sqm from the overall 40?

mickdw

Height of existing will govern you height wise on the extension.
You idea re a connecting hall is a good one.

Penn

whatisayis wrote: »

Hi and hope someone can clarify a few issues regarding the 40sqm planning exemption for a single house extension.

The house is an old cottage on an acre so there are no issues with boundary restrictions as there is more than 40m to the nearest boundary and much further to the nearest house. My questions:

Are there restrictions regarding length and width e.g. can you build 4m x 10m?

Would it be possible to build a double height extension e.g. 20sqm room upstairs and another 20sqm room downstairs without the need for permission?

The original walls of the cottage are nearly 60cm thick so we were thinking of connecting to the old house by constructing a closed in walkway of approx 3sqm from the original back door to what would be effectively a new building. Would this mean that we could disregard the depth of the original walls, which would not be directly connected to the new build, and just deduct the 3sqm from the overall 40?

That all sounds fine. As mickdw said, the main restrictions you're likely to face are the height restrictions, dependent on the height and rooftype of the existing cottage.

https://www.tipperarycoco.ie/sites/default/files/Publications/Doing%20work%20around%20the%20House%20-%20The%20Planning%20Issues.pdf

whatisayis

mickdw wrote: »

Height of existing will govern you height wise on the extension.
You idea re a connecting hall is a good one.

Thanks for the reply. So does that mean if the roof height remains the same as the original we would not need to get permission to construct a two story extension as long as the total internal area of the two floors does not exceed 37sqm (40 - the 3sqm walkway)?

Also, if we had internal insulation slabs, is the internal measurement taken from the slabs or the brickwork behind them?

Gumbo

whatisayis wrote: »

Thanks for the reply. So does that mean if the roof height remains the same as the original we would not need to get permission to construct a two story extension as long as the total internal area of the two floors does not exceed 37sqm (40 - the 3sqm walkway)?

Also, if we had internal insulation slabs, is the internal measurement taken from the slabs or the brickwork behind them?

Inside the slabs.
Confirm the max area of a first floor extension first, I think it’s 30 Sq. M in a detached setting.

whatisayis

kceire wrote: »

Inside the slabs.
Confirm the max area of a first floor extension first, I think it’s 30 Sq. M in a detached setting.

The way I read the regulations think the max for a first floor (which I am assuming is not the ground floor but upstairs?) is only 20sqm.

We were thinking of making the ground floor living room maybe 25sqm and the upstairs bedroom 15sqm. This would give us a bit more room to fit a staircase downstairs and enable us to put a velux on the roof to bring more light downstairs. Not sure if I am describing it well but do you know if that would be still classed withing the 40sqm allowance?

mickdw

whatisayis wrote: »

mickdw wrote: »

Height of existing will govern you height wise on the extension.
You idea re a connecting hall is a good one.

Thanks for the reply. So does that mean if the roof height remains the same as the original we would not need to get permission to construct a two story extension as long as the total internal area of the two floors does not exceed 37sqm (40 - the 3sqm walkway)?

Also, if we had internal insulation slabs, is the internal measurement taken from the slabs or the brickwork behind them?

Can you confirm if this is a single storey or 2 storey structure currently.

whatisayis

mickdw wrote: »

Can you confirm if this is a single storey or 2 storey structure currently.

It is a single story with two loft rooms - one at each gable end - which we use as bedrooms but they are not current regulation height to be classified as bedrooms.

We would need to build the extension at a lower level than the current house to meet height regulations. That wouldn't really be too much of a problem as the land slopes downwards from the house so we could have a step down to the new part.

I think we will probably end up just building a single story as we still can take advantage of the views and it seems the least troublesome option - hopefully easier to build, faster, and cheaper. We can maybe ensure the foundations that are put in would be capable of taking a second story should we change our minds later and decide to go through the planning process to extend upwards.

Thanks for taking the time to respond to my posts.