Building masonry Porch on front of stone house

IsThisOneFree

Hi All

I can't find a "building" forum on here, so I think DIY is probably the closest forum I can find

My Mum's house is a stone cottage, walls are about 2~3 feet thick. Currently there's a teak porch on the front with a clear Perspex roof. It's quiet old (about 20 years) and needs to be replaced now. We'd like to replace it with a masonry "block and mortar" porch instead with a hipped roof. The space is a little tight, and I've already done a basic design (in as much as you can design a square room with a door !!) including measurements, but before I start approaching local builders, I have a few questions (so that I'm fully aware of the options myself), so here goes:


1. I presume if this were a modern "blocks and mortar" building, the existing walls would have some block removed to create a finger type joint to attach the two structures (existing and new) together. However, this obviously isn't an option here, so what are our options ?

Having dome some searching, I found something called furfix - is this our best/only option ? Or what other options are available, and which would be the industry standard/recommendation (if any) ?

2. Possibly a somewhat open ended question, but how deep would the foundations need to be ? I've done some searching and found an old thread on here suggesting they would need to be 900mm. Would this be required even for a small "light" structure such as a porch ?

I have no idea how deep the foundations of the existing house are, I'm guessing it's unlikely that they're a meter deep (although the house has stood for over 100 years now !!) and would it be a problem if the new foundations were dug deeper than the existing ones (ie, could it cause the house to begin to move into the void until such time as it's been filled) ?

3. Following on from the above, given that the existing house probably does not have very deep foundations (or at the very minimum, has an unknown depth), do I need to be overly concerned about disturbing the existing foundations when this work is being done ?

4. Our house isn't very well insulated currently (that's a topic for another day !!) and while I don't want to go over insulating a room that won't be lived in, are there any recommendations on how much a porch should be insulated to avoid too much heat escaping through the front door, drafts etc etc ?

5. Kind of follows on from no. 4 above, and a pretty rookie question, but how thick would the blocks be that would be used in a construction such as this ?!?! I've googled this but found that there are lots of different thicknesses available. When I "specked up" my initial drawings, I based them on two layers of 4 inch blocks, with 4 inches of insulation in between. Does this sound about right ? Do I need to allow for any breathing space between the blocks and the insulation ?

OK, I think that's all my questions for now To any builders reading this .... it's not that I don't trust our local builders, I just feel that because the house is so old, there are things I might need to draw attention to any builders which might not be immediately obvious.

Thanks in advance

IsThisOneFree

Just realised there's a "Construction & Planning" forum that I should probably have used - I can't seem to delete this thread, so could a mod please move this if it's appropriate ?

Thanks !

paddy147

IsThisOneFree wrote: »

Hi All

I can't find a "building" forum on here, so I think DIY is probably the closest forum I can find

My Mum's house is a stone cottage, walls are about 2~3 feet thick. Currently there's a teak porch on the front with a clear Perspex roof. It's quiet old (about 20 years) and needs to be replaced now. We'd like to replace it with a masonry "block and mortar" porch instead with a hipped roof. The space is a little tight, and I've already done a basic design (in as much as you can design a square room with a door !!) including measurements, but before I start approaching local builders, I have a few questions (so that I'm fully aware of the options myself), so here goes:


1. I presume if this were a modern "blocks and mortar" building, the existing walls would have some block removed to create a finger type joint to attach the two structures (existing and new) together. However, this obviously isn't an option here, so what are our options ?

Having dome some searching, I found something called furfix - is this our best/only option ? Or what other options are available, and which would be the industry standard/recommendation (if any) ?

2. Possibly a somewhat open ended question, but how deep would the foundations need to be ? I've done some searching and found an old thread on here suggesting they would need to be 900mm. Would this be required even for a small "light" structure such as a porch ?

I have no idea how deep the foundations of the existing house are, I'm guessing it's unlikely that they're a meter deep (although the house has stood for over 100 years now !!) and would it be a problem if the new foundations were dug deeper than the existing ones (ie, could it cause the house to begin to move into the void until such time as it's been filled) ?

3. Following on from the above, given that the existing house probably does not have very deep foundations (or at the very minimum, has an unknown depth), do I need to be overly concerned about disturbing the existing foundations when this work is being done ?

4. Our house isn't very well insulated currently (that's a topic for another day !!) and while I don't want to go over insulating a room that won't be lived in, are there any recommendations on how much a porch should be insulated to avoid too much heat escaping through the front door, drafts etc etc ?

5. Kind of follows on from no. 4 above, and a pretty rookie question, but how thick would the blocks be that would be used in a construction such as this ?!?! I've googled this but found that there are lots of different thicknesses available. When I "specked up" my initial drawings, I based them on two layers of 4 inch blocks, with 4 inches of insulation in between. Does this sound about right ? Do I need to allow for any breathing space between the blocks and the insulation ?

OK, I think that's all my questions for now To any builders reading this .... it's not that I don't trust our local builders, I just feel that because the house is so old, there are things I might need to draw attention to any builders which might not be immediately obvious.

Thanks in advance

You are legally allowed to build a porch to a max size of 2 x 2 meters.

If you go anyway over that size then you need full planning permission before building any such porch.


Just be aware of that.:)

IsThisOneFree

drats ..... I literally just hit send on an e-mail to the local council to check out the planning requirements when I saw your reply The planned size is 1.4 x 1.7, so we should be good anyway ..... could have saved myself an e-mail if I'd just waited though !!

paddy147

IsThisOneFree wrote: »

drats ..... I literally just hit send on an e-mail to the local council to check out the planning requirements when I saw your reply The planned size is 1.4 x 1.7, so we should be good anyway ..... could have saved myself an e-mail if I'd just waited though !!

If you can and if the ground space and external cottage layout allows......then why not go to the max allowed size of 2 x 2 meters?

A nice front porch with some space will be a nice wellcome home for anyone entering the house.:)

IsThisOneFree

Didn't have my drawings infront of me last night ...... having though about it overnight, I realised that I must have made a mistake because a porch of 1.4 meters (minus 300mm each side for blocks) would basically be a very narrow hallway

Anyway, I mis-quoted myself originally.... the porch is 1.4M x 1.4M internally (floor space) - the actual footprint is 1.7M x 2M. I presume the 2x2 rule applies to the entire footprint of the porch, not the internal floor area, right ? You've actually raised a good point there though - I plan to make an "overhang" of 400mm (16 inches) of the roof over the front door, to provide some shelter in Winter when my Mum is coming come, so she can open the door in shelter. Technically, does this increase the footprint of the porch by 100mm ? Or does the rule already take into account the fact that the roof may be slightly larger than the strucutre ?

Anybody have any thoughts on my original questions at all ??

dathi

as i see you have a stone house be careful that it is not a protected structure, or in one of your councils "conservation areas" as it will need planing if it is.

IsThisOneFree

Thanks for the heads up dathi - I already mentioned this in my query to the local council office, so when they get back to me I'll query it further if they don't mention it.

martinn123

paddy147 wrote: »

You are legally allowed to build a porch to a max size of 2 x 2 meters.

If you go anyway over that size then you need full planning permission before building any such porch.


Just be aware of that.:)

I think its actually 2SqM, so thats 2 X 1

But check this out.

paddy147

martinn123 wrote: »

I think its actually 2SqM, so thats 2 X 1

But check this out.

Think Im wrong and you are right.:)


....."Building a front porch so long as it does not exceed two square metres in area and is more than two metres from a public road or footpath. If the porch has a tiled or slated pitched roof, it must not exceed four metres in height or three metres for any other type of roof".......

IsThisOneFree

For anybody interested, I beleive this is the material that paddy147 is referencing:

http://www.citizensinformation.ie/en/housing/planning_permission/planning_perm_altering_a_house.html

IsThisOneFree

Anybody have any ideas on my original questions at all ??

harry21

1. The thing you refer to as furfix - yes best option I think.

2. Foundation on firm ground and below frost line if possible. No other requirement. Structural dive not allowed by the way, so no further comment.

3. I would be amazed if the existing cottage has foundations. The excavation for the new foundation if 900mm wide would be unlikely to impact significantly on the existing structure.... unlikley IMO.

4. See below.

5. standard cavity is fine. What type of insulation are you taking about? A rigid insulation should not fill the entire cavity.

IsThisOneFree

Thanks for the reply harry21, much appreciated. Never occurred to me that the house might not have any foundations ! It's pretty much built on rock as far as we know (all around the house is very rocky .... which is another thing we need to consider before going ahead). Just one final question

Structural dive not allowed by the way

what's structural dive ? I googled it but it came up with nothing !

to everybody else, thanks for all the replies, I've contacted our local planning office and I'm waiting for a reply from them

harry21

IsThisOneFree wrote: »

Thanks for the reply harry21, much appreciated. Never occurred to me that the house might not have any foundations ! It's pretty much built on rock as far as we know (all around the house is very rocky .... which is another thing we need to consider before going ahead). Just one final questionwhat's structural dive ? I googled it but it came up with nothing !

to everybody else, thanks for all the replies, I've contacted our local planning office and I'm waiting for a reply from them

My spelling was bad. I was trying to say that structural advise is not allowed. .

Sorry for your wasted googling time!!

IsThisOneFree

You had me wondering if dive was some sort of funky subsidence Although even then, the sentence wasn't quiet making sense !!
Anyway, thanks for the clarification and the earlier advice