Cost of side extension?

Doozergirl

stuart45 said:

You can use 100mm cavity with something like K106 cavity board if space is really tight.

Or you can build with a modern method of construction and it would be less than 300mm.  

Structural Insulated Panels for sure, maybe others.  

Architects need to keep up with technology and building methods instead of going with exceedingly thick walls when there is barely room.  

silverwhistle

Doozergirl said:

Architects need to keep up with technology and building methods instead of going with exceedingly thick walls when there is barely room.  

What is sound attenuation like with some of these new techniques? I've a ~1952 ex-council terrace with very solid walls and don't hear much from my neighbours. I'd like an extension too but am a bit dubious about some modern homes. I may be being unfair, but ultimately don't really have enough experience to judge.

Bigphil1474

Probably would be permitted development but there's a few rules to check out. This is a good summary:-

https://ecab.planningportal.co.uk/uploads/miniguides/extensions/Extensions.pdf

For a single storey side extension of 2mx8m, I can't see anything that would say it isn't PD.

greensalad

Doozergirl said:

stuart45 said:

You can use 100mm cavity with something like K106 cavity board if space is really tight.

Or you can build with a modern method of construction and it would be less than 300mm.  

Structural Insulated Panels for sure, maybe others.  

Architects need to keep up with technology and building methods instead of going with exceedingly thick walls when there is barely room.  

What sort of cladding do you normally do on these? What is appropriate? Is it cheaper than blockwork?

I ask because I'm still part-dreaming about our future extension to replace the conservatory. Builder told me it's a cheap job because it's only two walls. I want it clad in composite shiplap and want to redo the shiplap on our dormer extension at the same time to match as I think it'll look nice. And I'm presuming it's a lot cheaper than brickwork? I was looking at some other insulted board type things but this ice cream sandwich looks interesting.

Doozergirl

greensalad said:

Doozergirl said:

stuart45 said:

You can use 100mm cavity with something like K106 cavity board if space is really tight.

Or you can build with a modern method of construction and it would be less than 300mm.  

Structural Insulated Panels for sure, maybe others.  

Architects need to keep up with technology and building methods instead of going with exceedingly thick walls when there is barely room.  

What sort of cladding do you normally do on these? What is appropriate? Is it cheaper than blockwork?

I ask because I'm still part-dreaming about our future extension to replace the conservatory. Builder told me it's a cheap job because it's only two walls. I want it clad in composite shiplap and want to redo the shiplap on our dormer extension at the same time to match as I think it'll look nice. And I'm presuming it's a lot cheaper than brickwork? I was looking at some other insulted board type things but this ice cream sandwich looks interesting.

Ice cream sandwich! 

Not cheap to buy but very quick to install and far less messy than traditional build. 

You can clad in anything as if you were cladding over a block wall.  Needs batons/cross-batons and the product of your choice - shiplap would work perfectly but you can also use a render board, for example.  

GDB2222

We would want to hang kitchen unit cupboards on the walls. Are Structural Insulated Panels strong enough, or would they need a lot of help to spread the load? 

Eldi_Dos

Must say the thought of applying for Party Wall Agreement when next door is a cemetery kind of gave me a tickle.

Sorry will get back to my soup.

Doozergirl

GDB2222 said:

We would want to hang kitchen unit cupboards on the walls. Are Structural Insulated Panels strong enough, or would they need a lot of help to spread the load? 

Plenty strong enough.  They're structural timber.  OSB facing inside so you have your strength there.  

ComicGeek

Doozergirl said:

GDB2222 said:

We would want to hang kitchen unit cupboards on the walls. Are Structural Insulated Panels strong enough, or would they need a lot of help to spread the load? 

Plenty strong enough.  They're structural timber.  OSB facing inside so you have your strength there.  

Although you'll want to batten internally to create a services void for running cables etc. You can't chase into the SIPs like you do with blockwork.

If you're looking at brickwork as an external finish, I don't see that SIPs gives a significant reduction in overall wall thickness against traditional masonry construction. The saving in wall thickness is more to do with flexibility in external cladding systems.

We have lots of projects that start off as SIPs but quickly change to traditional timber frame or masonry by the time they reach site. Mainly down to lack of builders willing to engage with it, it massively reduces their own profits and slice of the pie. Can work for true self-builds or where people manage the different contracts themselves, but difficult finding anyone in our area that will take on a SIPs scheme - particularly when large amounts of money have to be paid out to the SIPs companies before delivery, with a risk of them going under and all the money lost. 

FreeBear

ComicGeek said:

Doozergirl said:

GDB2222 said:

We would want to hang kitchen unit cupboards on the walls. Are Structural Insulated Panels strong enough, or would they need a lot of help to spread the load? 

Plenty strong enough.  They're structural timber.  OSB facing inside so you have your strength there.  

Although you'll want to batten internally to create a services void for running cables etc. You can't chase into the SIPs like you do with blockwork.

One would plan ahead and have conduit put in at the factory - Requires some serious thinking and detailed drawings well ahead of time. If Huf Haus can manage to do it with their flat-pack homes, I don't see why a UK SIPS manufacturer can't.