Advice on a small extension for the rear of house

i_dont_know

Hi, Just wondering if anyone has any advice, tips etc. on extensions and extension types.

Looking to add an extension to the back of a small townhouse.

The townhouse is 65sqm and I'm looking to add a 17sqm rear extension. There is access to the garden via a regular garden gate at the end of the garden. The garden is level and (fairly) square.

My main concern is the fact the garden backs onto a busy road. Roadnoise in the upstairs and downstairs rear rooms is already an issue, there is triple glazing in both. Building the downtairs even closer to this road is going to make things louder, so whatever type of extension built will have to try and cut the noise down as much as possible.

Does anyone have any experience or info on -snip- extensions with regards blocking outside noise? Would a block extenion be better than a prefabricated building? Has anyone had a similar issue when building an extension?

It would also have to be a flat roof, any advice on construction materials to also help block roadnoise?

Finally, can anyone give a ballpark figure of current extension costs in the Dublin area. It would just be a bog standard room with a few electrical sockets and a radiatior. A door to the garden and a couple of windows. No kitchen or bathroom going in as it will be used to extend the sitting room.

As you can probably tell cutting down on the incoming roadnoise would be an important factor on how we decide to go ahead.

Any advice etc would be greatly appreciated. Cheers.

Gumbo

First off, do you need planning?

i_dont_know

As there would be slightly less than 25sqm of garden space left then yes we'd have to apply.

One of the houses in the same complex applied for a similar extension and they were granted permission so hopefully that won't be an issue. No of our neighbours say they have any objection either.

Gumbo

i_dont_know wrote: »

As there would be slightly less than 25sqm of garden space left then yes we'd have to apply.

One of the houses in the same complex applied for a similar extension and they were granted permission so hopefully that won't be an issue. No of our neighbours say they have any objection either.

Perfect, that's the first step.
Now, have you engaged a local Planning Agent Architect, Technician, Surveyor or similar?

Idbatterim

There isn’t much difference sound insulation wise between double and triple glazed. You need acoustic glass, huge difference there. You can get the glass only and keep frames ...

Concrete has a big mass , so good for noise reduction. Best in mind your weakest link. If one area is poor for noise , doesn’t matter how good the rest of it is ... You can get soundblock plasterboard etc that helps reduce noice ...

In terms of the existing windows and noise. You could go for secondary glanzing. It’s one thing in living rooms/ kitchen , but if there are used bedrooms at back of house, road traffic noise is horrendous!

Watch this op...

https://m.youtube.com/watch?v=ZKaIAlSOACY

Even an old air vent will let a lot of noise in...

i_dont_know

kceire wrote: »

Perfect, that's the first step.
Now, have you engaged a local Planning Agent Architect, Technician, Surveyor or similar?

We haven't started this process yet as we're trying to figure out if it's something that's even worth considering. Not sure if it's 30K, 50K or 80k type of ballpark figure.

Obviously if it was huge money for such a small extension on such a small townhouse it wouldn't make sense to move ahead with it.

i_dont_know

Idbatterim wrote: »

There isn’t much difference sound insulation wise between double and triple glazed. You need acoustic glass, huge difference there. You can get the glass only and keep frames ...

Concrete has a big mass , so good for noise reduction. Best in mind your weakest link. If one area is poor for noise , doesn’t matter how good the rest of it is ... You can get soundblock plasterboard etc that helps reduce noice ...

In terms of the existing windows and noise. You could go for secondary glanzing. It’s one thing in living rooms/ kitchen , but if there are used bedrooms at back of house, road traffic noise is horrendous!


Even an old air vent will let a lot of noise in...

Yeah I've gotten a couple of quotes for secondary glazing. Due to the size and strange angles that the windows are at we've been quoted between 2 and 3 grand just for one bedroom. Also, this wouldn't address any noise coming in via ceiling extra.