Extension, best wall construction

ks44

Hi all,
Planning on building a small extension to my kitchen/Living area in a semi d, approx 20m2.
Existing house is constructed with hollow block (i know its frowned upon!!).
Total wall width is approx 305mm. It seems to be 215mm hollow block,50mm insulated board inside on 40mm battens.
I would like to try and keep the same wall width.
Should i continue with the hollow block or change to a cavity wall (100mm outer and inner leaf with 80mm cavity).
If i change and have insulation in the cavity, will there be a problem where the old meets new?

Thanks in advance for any response.

Calahonda52

As a matter of interest will the join to the old wall by new involve leaving a small nib, assuming you are knocking out an existing wall?

Also in the old wall are the external wall vents ducted past the battens to the insulated pb: u will need to take off a wall vent to see?

You might get ideas here, with the ACDs
http://www.environ.ie/en/TGD/
or here
https://www.nsai.ie/S-R-54-2014-Code-of-Practice.aspx
or the pdf

Gumbo

ks44 wrote: »

Hi all,
Planning on building a small extension to my kitchen/Living area in a semi d, approx 20m2.
Existing house is constructed with hollow block (i know its frowned upon!!).
Total wall width is approx 305mm. It seems to be 215mm hollow block,50mm insulated board inside on 40mm battens.
I would like to try and keep the same wall width.
Should i continue with the hollow block or change to a cavity wall (100mm outer and inner leaf with 80mm cavity).
If i change and have insulation in the cavity, will there be a problem where the old meets new?

Thanks in advance for any response.

I have the same construction on the gable wall of my house. (Built circa 1995).

When I'm doing my extension next year I was leaning towards 215 solid block on flat along boundary (helps compliance with Part E (sound)) and maybe batton out and fix insulated board to the battons. This will leave us with a small service gap at the back if we wanted to run cables for tv mounting etc

But I'm not confirmed on that detail yet so will follow this thread with interest.

ks44

Thanks for reply Calahonda.

I have attached a drawing which i done up so you have an idea of what i am doing. ( I'm no expert. I work in groundworks and do some Autocad work).

I popped off vent and they are ducted through with a 4" pipe.

I am currently undecided as to what i am doing on the party wall side. I may step in slightly to keep everything on my side and have a standard gutter, etc. Otherwise i will be into a parapet. Any thoughts?

My neighbour is very easy going and will be happy with whatever i want.

Gumbo

ks44 wrote: »

Thanks for reply Calahonda.

I have attached a drawing which i done up so you have an idea of what i am doing. ( I'm no expert. I work in groundworks and do some Autocad work).

I popped off vent and they are ducted through with a 4" pipe.

I am currently undecided as to what i am doing on the party wall side. I may step in slightly to keep everything on my side and have a standard gutter, etc. Otherwise i will be into a parapet. Any thoughts?

My neighbour is very easy going and will be happy with whatever i want.

I would personally agrees detail with the neighbour to do the parapet. It can be constructed structurally do he can use the wall in the future and I looks better on elevation as if you step in, then your neighbour will have to step in and you are left with this empty space in between.

Have a look at the pics in my signature, we recently done the same for my parents house.

Also don't forget you will need to allow piers for the steel beams which are not shown on your drawing.

Calahonda52

ks44 wrote: »

0: Thanks for reply Calahonda.

1: I have attached a drawing which i done up so you have an idea of what i am doing. ( I'm no expert. I work in groundworks and do some Autocad work).

2: I popped off vent and they are ducted through with a 4" pipe.

3: I am currently undecided as to what i am doing on the party wall side. I may step in slightly to keep everything on my side and have a standard gutter, etc. Otherwise i will be into a parapet. Any thoughts?

4: My neighbour is very easy going and will be happy with whatever i want.

0:
1: nice work, : u might keep the paving, what is story with existing steel beam/lintel allowing ope into leanto.
2: good: common problem with heat loss when not ducted.
3: parapet wall with "valley" wide enough to walk on, u may need to move doors to right a bit. I would consider fibreglass "valley".. its not quite a valley but am supposed to be watching the 3 year old grandhild so gone blank.:)
4: ....:D:D ....until you start.... this forum loaded with such issues. KC on the money here re agreeing it in writing, the link below will guide you as to the respective rights.
http://www.irishstatutebook.ie/eli/2009/act/27/section/43/enacted/en/html

If u use google advanced search and boards.ie as the domain, u can find previous threads on boundary wall issues, including ones I added this link to.

I have always used the 215 sold on flat for such walls: the extreme case, with anther 100 block to support a custom made Alu or SS seamless gutter into which the valley is flashed: rolls royce maybe but 100 mm in a 6m room wont be missed

ks44

Thanks for the great input.

Kceire, that extension looks great. Exactly the type of thing i'm going for, exept less glass (don't think i could stretch to that!)
The detail with the neighbouring property looks perfect. I think i will try and achieve something like that.

Two neighbours with the same house as mine both extended. Both of them removed the existing Steal Beam that is accommodating the lean-to and replaced it with one spanning the full width of the house.

Calahonda52

did they get the clean lines u show without any nib to support the beam, especially with hollow block?

is the ceiling line clean as well?

ks44

Calahonda52 wrote: »

did they get the clean lines u show without any nib to support the beam, especially with hollow block?

is the ceiling line clean as well?

I not sure. I am concerned about that myself. The same builder did both. I am going to knock in tomorrow and check it out and quiz them on it.

Calahonda52

ks44 wrote: »

I not sure. I am concerned about that myself. The same builder did both. I am going to knock in tomorrow and check it out and quiz them on it.

Good idea, no point in she who must be obeyed expecting a clean line along the worktop and then u have to put in a nib

I usually go for a steel column at each end onto a pad footing: a bit more steel but its much less ambiguous for the engineer to sign off on there being adequate bearing.