New Roof/Insulation question

marius

I need to replace the flat felt roof on my house - it is a pretty small (66sq m) bungalow.

There are a few questions I have about this (im a total retard when it comes to construction).

1) The house is an ice box and I am going to need to insulate the entire thing. In general is it possible to insulate the walls when the roof is taken off? They are cavity block walls - can insulation be poured into these? I have heard it is possible and relatively cheap but that it can be flaky enough and can lead to having 'cold spots' where the insulation is not evenly dispersed.

2) As I am replacing the flat roof it is a great opportunity to put a second floor on the house. I am looking at adding a second floor of approx 40sq m. Just wondering what the ballpark figure for something like this is? I know it can vary significantly depending on exactly what I want to do. I am looking to have 2 bedrooms and a bathroom in the new 'upstairs'. Is there a ballpark cost per sqm for something like this?

I have an budget of about 40K - just wondering if this is realistic or not in todays market? (this will have to include architect fees/planning fees etc.)

Anyone done anything similar to this?(i.e. adding another floor to a bungalow)

Any help appreciated.

Wonky Knees

marius wrote: »

I need to replace the flat felt roof on my house - it is a pretty small (66sq m) bungalow.

There are a few questions I have about this (im a total retard when it comes to construction).

1) The house is an ice box and I am going to need to insulate the entire thing. In general is it possible to insulate the walls when the roof is taken off?

Yes it is.

They are cavity block walls - can insulation be poured into these?

Yes different types can be pumped in with varying degrees of success.

I have heard it is possible and relatively cheap but that it can be flaky enough and can lead to having 'cold spots' where the insulation is not evenly dispersed. True but can still be a big improvement.

2) As I am replacing the flat roof it is a great opportunity to put a second floor on the house. I am looking at adding a second floor of approx 40sq m. Just wondering what the ballpark figure for something like this is? I know it can vary significantly depending on exactly what I want to do. I am looking to have 2 bedrooms and a bathroom in the new 'upstairs'. Is there a ballpark cost per sqm for something like this? No

Too many variables here. Foundations may have to be dug, pads put in, use of steel frame support depending on the type of construction. Since cavity block is downstairs you may have to use cavity block upstairs, which is fine as long as the structure is sound and you use at least 100 mm internal insulation (could also go for an external insulation board. other thing to consider is size and type of windows.

You will need an architect to do a drawing and an engineer to spec the structural aspect of the build. That said if you have a good builder in mind bring him out to the site and ask for opinion, he shouldn't be too far off.

I have an budget of about 40K - just wondering if this is realistic or not in todays market? (this will have to include architect fees/planning fees etc.)

Anyone done anything similar to this?(i.e. adding another floor to a bungalow) Added another floor to a cavity block extension on a semi-d.

Any help appreciated.

Good luck:)

muffler

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RKQ

marius wrote: »

1) The house is an ice box and I am going to need to insulate the entire thing. In general is it possible to insulate the walls when the roof is taken off? They are cavity block walls - can insulation be poured into these? I have heard it is possible and relatively cheap but that it can be flaky enough and can lead to having 'cold spots' where the insulation is not evenly dispersed.

Great idea but technically taking off the roof & cavity closer will not make insulating the walls any easier. Pumped insulation - fibre or bead - is pumped in at certain centres. Wheather the roof is On or Off is of no benefit, from an installers viewpoint. (in fact pumping walls without a cavity closer - cavity exposed - would be almost impossible)

marius wrote: »

2) As I am replacing the flat roof it is a great opportunity to put a second floor on the house. I am looking at adding a second floor of approx 40sq m. ..... Is there a ballpark cost per sqm for something like this?

Circa €100 per square foot. But it makes great sense to build a dormer roof now. Contact a local Architectural Technician with a good reputation and full PI insurance. Discuss your ideas, he / she will recommend a good Structural Engineer to inspect existing walls, foundations etc and possibly design any ring beam or steel beams that may be required.

Your Arch Tech will apply for Full planning permission on your behalf. Provide working drawing and detailed tender documents.

I can't give an accurate costing - but increase in joist sizes, new gable walls etc - well worth doing IMO once you have planning permission. The best way to find out if €40k is enough is to get 3 written quotes from at least 3 local Builders (or 3 Roofers, 3 blocklayers, 3 plasterers etc). I reckon its possible. Good luck.

marius

Cheers Lads, really appreciate the replies. First time at this and just trying to get an idea for where to start etc.

RKQ wrote: »

But it makes great sense to build a dormer roof now.

This is the plan actually, a tall enough dormer roof is pretty much all we need.

RKQ wrote: »

Contact a local Architectural Technician with a good reputation and full PI insurance. Discuss your ideas, he / she will recommend a good Structural Engineer to inspect existing walls, foundations etc and possibly design any ring beam or steel beams that may be required.

Will do! Have a few friends/family who have had work done so will see if they have any recommendations...

fatimamansions wrote: »

Too many variables here. Foundations may have to be dug, pads put in, use of steel frame support depending on the type of construction. Since cavity block is downstairs you may have to use cavity block upstairs, which is fine as long as the structure is sound and you use at least 100 mm internal insulation (could also go for an external insulation board. other thing to consider is size and type of windows.

Yeah - I really want to insulate the crap out of the place, need to investigate all my options here... Will be using low U Double glazing through out which will add a few quid but im prepared to pay a little more to have the whoole place insulated well.

Cheers again lads...

Irish Energy

marius wrote: »

1) The house is an ice box and I am going to need to insulate the entire thing. In general is it possible to insulate the walls when the roof is taken off? They are cavity block walls - can insulation be poured into these? I have heard it is possible and relatively cheap but that it can be flaky enough and can lead to having 'cold spots' where the insulation is not evenly dispersed.

Marius, i am a civil engineer that works for an insulation company and i can tell you that Pumping any type of insulation into cavity blocks is not recommended and is not good practice. It leaves loads of thermal bridging (cold spots) and can cause huge problems down the line with condensation and then mould growth. Sustainable energy Ireland give grants for cavity fill insulation but they will not give you it if you fill cavity blocks for the reasons above.
Internal or external wall insulation is the only proper solution for cavity blocks. plus the grants can cover the entire cost of internal insulation, the grant for pumped insulation will not cover the entire cost.