20m2 extension - cost

Unwilling

SB note Moved from another thread

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I am trying to figure out how much at 20 square meter extension to our terraced house would be. Apex roof, knocking out the back wall putting. Coverting current galley kitchen into the utility.
I know what we want done, and it's been done in other houses, so architect is not required.
However, before I go enlisting builders, i want to see if I can afford it first.
Am I talking 20k or 50k¬

Finding it impossible to ascertain!!!!

.

sinnerboy

Unwilling wrote: »

so architect is not required.

Unwilling wrote: »

Finding it impossible to ascertain!!!!

architect is not required

Unwilling

Sinnerboy - sorry, can you clarify your post. Why do I need an architect?

sinnerboy

Because as much as - with all respect to you - you believe that what you want done is all so clear and has been done before you do need an architect to accurately specify the works. Then you have documents that can be priced by different contractors where you can be confident that all are pricing exactly the same works.

whelzer

Unwilling, I'm approx 60% through a 75m2 extension(s) and rennovation job. I needed planning so got an architect for that but have managed build myself. I got around 9 builders quotes and they ranged from 160k to 77k - I'm gettin a lot done!

I ended up somewhere in the middle and am getting a super insulated extended house.

I'd agree with Sinnerboy, get a professional to do a spec/tender for you, doesn't "need" to be an architect though, I'd say an engineer/AT could fo a job for such a "small" project. That way you can compare like for like when you get quotes in. It was truely amazing lining up several quotes pricing the exact same thing, new stairs, external walls, etc. Difference was amazing.

Reckon you'll get basic build for < 20k, this would include electrics and plumbing. A (small) kitchen can cost 2-20k so its very hard to comment on that sort of thing/finishing costs. I'm in Dublin btw.

sinnerboy

whelzer wrote: »

doesn't "need" to be an architect though, I'd say an engineer/AT could fo a job for such a "small" project.

+1

slave1

Interesting thread, I'm seriously thinking of a basic extension onto the rear of the house around 20m2 so similar enough, I will use existing rear window as entrance to extenstion so no need for 'knock-out'. Lean-to tiled roof and two simple windows so really a box onto the rear of the house in as simple a form as they come. Electrics will be basic sockets and lighting. Unfortunately I have no rear access so I am expecting a cost hit there (foundations/materials movemment) and the main sewer access will need to be moved a few feet. All insulation will be of the highest spec. I can afford as I believe that's where the money should be spent. I'm in the midlands so cost comparision should be interesting.
No plans drawn up given 'simplicity' of build.
I've just started the process of builder quotes and then will move onto direct labour quote.

Whilst I'm here, what's spec. floor/cavity/plasterboard insulation would folk recommend?

bigmanhole

Really depends on specification but generally 20m2 x 10.763 (to convert to sq.ft) x €150 a sq.ft = 32,389 - probably 30k

bigmanhole

Whilst I'm here, what's spec. floor/cavity/plasterboard insulation would folk recommend?[/QUOTE]

100mm K3 in Floor
60mm K8 in Walls with 50mm air gap
140mm K7 in roof leaving 50mm air gap for ventilation

whelzer

slave1 wrote: »

Whilst I'm here, what's spec. floor/cavity/plasterboard insulation would folk recommend?

I'm getting 300mm eps in the floor/foundation giving a very low uv value.
Walls are acc blocks with 200mm eps external insualtion - no cavity.
Roof is a warm jobby with 100mm rockwool & 200mm eps.

Toasty!:rolleyes:

bigmanhole

whelzer wrote: »

I'm getting 300mm eps in the floor/foundation giving a very low uv value.
Walls are acc blocks with 200mm eps external insualtion - no cavity.
Roof is a warm jobby with 100mm rockwool & 200mm eps.

Toasty!:rolleyes:

Very toasty!!! Only thing is if its just a 20m2 extension theres prob not much point in going overboard with insulation as the rest of the house wont be up to that standard and once you exceed the regs significantly your guaranteed a warm extension. Insulation costs do add up.

slave1

Forgive my general ignorance on the specifics of insulation.
1970 Semi - I have previously studed all external walls with 50mm Xtratherm and have cavity wall filled with pumped foam insulation, all windows are double glazed uPVC, some of the more recent replacements Low-E/argon filled etc. Some floors taken up and 100mm insulation retro-fitted.
Home is nice and warm at present, two buckets of coal is sufficent to heat the home to tee-shirt level for 24 hours (Stanley Erin multi-fuel stove).
Home is NEVER cold in the mornings, even over recent cold spell.

So you see I want to ensure the best insulation I can get in order to avoid creating a new room that would suck heat and reduce all good work to date, given it will adjoin the kitchen/dining open area, morning comfort is important.

100mm K3 in Floor
60mm K8 in Walls with 50mm air gap
140mm K7 in roof leaving 50mm air gap for ventilation

Thank you

100mm K3 = Kingspan product here, yes?

60mm K8 = Kingspan product here, yes?

140mm K7 roof = Kingspan product here, yes?


I was also envisaging some level of insulated plasterboard, might as well stay with Kingspan, say K18, this guy.

This seem like a good plan?

@whelzer

Unfamiliar with what you are recommending, sounds goods and a search came up with this article, I think that given my knowledge and probable direct labour route this may be over stretching my scope (also taking into account expertise in this area).

slave1

bigmanhole wrote: »

Really depends on specification but generally 20m2 x 10.763 (to convert to sq.ft) x €150 a sq.ft = 32,389 - probably 30k

Sorry, didn't notice this post, eyes went to insulation advice. For my build it's builder finish, there will be nothing going into this room apart from carpet and existing furniture/electrical items, literally a rectangle box. I will paint/woodwork to personal level.
My thoughts (to be confirmed) are <€20k.

bigmanhole

slave1 wrote: »

Forgive my general ignorance on the specifics of insulation.
1970 Semi - I have previously studed all external walls with 50mm Xtratherm and have cavity wall filled with pumped foam insulation, all windows are double glazed uPVC, some of the more recent replacements Low-E/argon filled etc. Some floors taken up and 100mm insulation retro-fitted.
Home is nice and warm at present, two buckets of coal is sufficent to heat the home to tee-shirt level for 24 hours (Stanley Erin multi-fuel stove).
Home is NEVER cold in the mornings, even over recent cold spell.

So you see I want to ensure the best insulation I can get in order to avoid creating a new room that would suck heat and reduce all good work to date, given it will adjoin the kitchen/dining open area, morning comfort is important.


Thank you

100mm K3 = Kingspan product here, yes?

60mm K8 = Kingspan product here, yes?

140mm K7 roof = Kingspan product here, yes?


I was also envisaging some level of insulated plasterboard, might as well stay with Kingspan, say K18, this guy.

The K3\8\7 as detailed would probably match easily what your existing house has (which is warm as it is) some people go crazy insulating (and thus spending money) which is not necessary - K18 on the walls on top would be the icing on the cake. Also people say some of the other brands are equal to Kingspan but IMO they are not

bigmanhole

slave1 wrote: »

Sorry, didn't notice this post, eyes went to insulation advice. For my build it's builder finish, there will be nothing going into this room apart from carpet and existing furniture/electrical items, literally a rectangle box. I will paint/woodwork to personal level.
My thoughts (to be confirmed) are <€20k.

Id agree for builders finish back at 100euro sq.ft thus 22k ish

galwaytt

bigmanhole wrote: »

Id agree for builders finish back at 100euro sq.ft thus 22k ish

That's for the build of the new part, yes, but as recent experience has shown me, the cost of dealing with what's there already is 'unknown'. For instance, are there path's/drives to be removed ? If so, are there services underneath (water, sewer, power) ? And demolition or modification to existing structure to accomodate the new build (linteling, walls etc).

The cost of that needs to be added to figure you have, imho.

slave1

Fair points, just a modest back path to be removed, I could do it in a half-day so not a large sum, existing window will provide access so relativley straightforward as no lintel etc required, again I could do in a day myself.

Sewer access does need to move, anyhow as the quotes start I'll touch base with updates.

bruschi

slave1 wrote: »

Forgive my general ignorance on the specifics of insulation.
1970 Semi - I have previously studed all external walls with 50mm Xtratherm and have cavity wall filled with pumped foam insulation, all windows are double glazed uPVC, some of the more recent replacements Low-E/argon filled etc. Some floors taken up and 100mm insulation retro-fitted.
Home is nice and warm at present, two buckets of coal is sufficent to heat the home to tee-shirt level for 24 hours (Stanley Erin multi-fuel stove).
Home is NEVER cold in the mornings, even over recent cold spell.

So you see I want to ensure the best insulation I can get in order to avoid creating a new room that would suck heat and reduce all good work to date, given it will adjoin the kitchen/dining open area, morning comfort is important.


Thank you

100mm K3 = Kingspan product here, yes?

60mm K8 = Kingspan product here, yes?

140mm K7 roof = Kingspan product here, yes?


I was also envisaging some level of insulated plasterboard, might as well stay with Kingspan, say K18, this guy.

This seem like a good plan?

@whelzer

Unfamiliar with what you are recommending, sounds goods and a search came up with this article, I think that given my knowledge and probable direct labour route this may be over stretching my scope (also taking into account expertise in this area).

the other thing, Kingspan is probably the most expensive insulation material that is available here. try xtratherm and rockwool for equivalent products. there may be a thickness change in their products to match the spec, but cost significantly less.

galwaytt

bruschi wrote: »

the other thing, Kingspan is probably the most expensive insulation material that is available here. try xtratherm and rockwool for equivalent products. there may be a thickness change in their products to match the spec, but cost significantly less.

...as I posted elsewhere today, all Rockwool going up by 8% from Feb 1. This is but one of a raft of increases in materials planned for Q1 this year from all the big players.

bruschi

galwaytt wrote: »

...as I posted elsewhere today, all Rockwool going up by 8% from Feb 1. This is but one of a raft of increases in materials planned for Q1 this year from all the big players.

yeah xtratherm have also confirmed they are increasing prices (approx 5%), and was told by Kingspan that they had an increase at the end of last year, so they should remain stable from now on, once those increase kick in.

smelly sock

sorry for digging up an old thread lads,

Slave how did you get on in the end for pricing etc?