Rebuilding outer leaf

[allthatpebbledash]

In planning stages of a deep retrofit. House is detached, and neighbouring houses are brick, various shades of red and brown. Some have been rendered to the sides over years.

 

My house is the same I suspect. Make up of the existing walls is ‘50-60s brick cavity walls with some mineral wool blown in place, and other half (previously built extensions) is dual skin blockwork with 50mm PIR in the cavity. Approx cavity in all the walls is 75mm.

 

All the walls are covered in pebbledash!
 

As part of deep retrofit, I will be having all new ground floor structure and intermediate floor, a full new roof, all new windows and doors, and rebuilding the rear wall of the house due to structural complications and building a modern rear extension. That’s just to give idea of what project entails.

 

Question is, how should I freshen up the rest of the house?

 

Option 1.

Remove pebbledash, inspect underlying brickwork/blockwork and make good, render over.

 

Option 2.

Remove pebbledash, inspect underlying brickwork/blockwork and make good, leave original brick as finish. Where there is blockwork, render over.

 

Option 3.

Leave pebbledash in situ, inspect to make sure no cracks etc, fix EWI straight on top and render over.

 

Option 4.

Take down external leaf, replace insulation with full fill cavity batts, probably wool, inspect wall ties etc, rebuild with nice red brick as finish.

(Being red bricks are cheapest around, but it’ll allow the house to blend right in the street scene too.)

 

Option 5.

Take down external leaf, replace insulation with full fill cavity batts, probably wool, inspect wall ties etc, rebuild external using blockwork and render over.

 

I have some understanding of the costings involved based on initial conversations with a few trades. Based on 200 sqm of external wall.

 

Remove pebbledash £20 sqm

Render £60-140 sqm (pending type)
Blockwork £25 sqm

Bricks £30-£60 sqm (pending type)

EWI £40+ sqm (min 50mm)

Wool batts £18 sqm (min 75mm)

 

I feel option 4 would be the best overall.

 

But.

 

Would love to hear some thoughts and ideas if there are other ways? Or if someone else has done something similar, how did it go? Lessons learned?

 

Thanks.

 

[Conor]

Option 6. Demolish the lot and start again. What you are planning to do will cost more and perform worse than a new build.

[Canski]

You are not going to get brickwork or blockwork supplied and fitted for those rates. I'm unsure about the other items.

[Redbeard]

Are you doing all the work yourself? I am not sure where the £40/m2 for EWI came from, even at only 50mm. The '+' must be a very big +! For years 'around £100' has been the regular cry and it very rarely comes in at that. Including 'enabling works I have seen it well over £160/m2.

[Iceverge]

2 hours ago, allthatpebbledash said:

Question is, how should I freshen up the rest of the house?

 

 

2 hours ago, allthatpebbledash said:

Option 1.

 

2 hours ago, allthatpebbledash said:

 

 

2 hours ago, allthatpebbledash said:

Option 2.

2 hours ago, allthatpebbledash said:

Option 3.

2 hours ago, allthatpebbledash said:

Option 4.

2 hours ago, allthatpebbledash said:

Option 5.

[joe90]

Yes I was thinking knockdown and rebuild properly And get the VAT back.

 

[Russell griffiths]

You are 100% not going to do option 4 or 5 never heard such a ludicrous idea. 
there’s been a few silly ideas on here in the past, but I’m afraid you have just topped them all. 

[Mike]

5 hours ago, allthatpebbledash said:

Option 2.

Remove pebbledash, inspect underlying brickwork/blockwork and make good, leave original brick as finish. Where there is blockwork, render over.

 

Option 3.

Leave pebbledash in situ, inspect to make sure no cracks etc, fix EWI straight on top and render over.

One of these. Which one depends on the state of the pebbledash - in particular evidence of cracking or sounding hollow.

 

However a deep retrofit will be more expensive and time-consuming that rebuiding. Unless you do lots yourself, in which case it may be cheaper but will take much longer...

 

5 hours ago, Conor said:

Option 6. Demolish the lot and start again. What you are planning to do will cost more and perform worse than a new build

...so give this very serious consideration!

[Benpointer]

Option 4 or 5 will surely lead to Option 6 in an uncontrolled way.

 

If you really don't want to rebuild, then Option 3 but aim for more than 50mm EWI.  

 

 

[Mattg4321]

With that much work it’s going to be cheaper and better to knock it down and start again, doing it properly. 

[Iceverge]

@allthatpebbledash, I hope I wasn't poking too much fun with my above post. Sorry if I was. 

 

Practically what you are proposing is possible but very uneconomical. It's been alluded in the above posts that with lots of DIY that it could be cheaper. I made the mistake in our old build of not valuing my time enough. I embarked on circuitous routes because of it and it pretty much burnt me out. 

 

If you really want to avoid a knock and rebuild then I would step back from the bleeding edge of performance a little. 

 

Dig out the ground floor and replace with 300mm EPS. Pour a slab with UFH or float an OSB floor on top. 

 

Suck out the mineral wool in the walls, replace with EPS beads. 

 

Parge internal walls and apply good airtighess to all joists and wall penetrations. Apply a battened internal service cavity with mineral wool insulation. Plasterboard and skim 

 

Install good quality 3g PVC windows and doors.

 

Apply an airtight membrane to the ceiling of the existing roof. Pump 3-400mm of cellulose in there.

 

Install dMEV or ideally dMVHR if possible. 

 

You'll get to about 30kWh/m²/annum like this I reckon and it can be done piecemeal. 

 

Otherwise knock and rebuild. 

Edited December 17 by Iceverge

[Ferdinand]

I think mine has the outer leaf rebuilt, but it was a bungalow having an extra storey added and was done by the previous owners who lived in a caravan for several years. They also did a side extension and a fat-at-the-back extension. We bought it finished except for a conservatory and the electric gates. The caravan is still on the Council database 15 years later.

The weakness I see with redoing the outer leaf is that it will never be high performance with only a 75mm cavity and 50mm EWI. That feels like more cost than benefit. I only have 80mm PIR (it needed double) in the cavity and is better than OK, but only an EPC of low-80s iirc without the large solar array.

Your costs need a careful check. I have had various EWI quotes for different houses over the years, typically for 125-200mm to be worth the pfaff, and they have never come out at less than £100 per sqm even going back a decade and with agreements for me to get various prep work done.

I'd say consider option 6 if you can, and a design-and-build from a timber frame company (or design-and-shell and you do fit-out-and-decorate), and bank the several extra years of spare time you get for you or your family to enjoy.

Ferdinand

 

[Jilly]

Maybe all the videos laboured the point …

Edited Wednesday at 07:54 by Jilly

[allthatpebbledash]

21 hours ago, Conor said:

Option 6. Demolish the lot and start again. What you are planning to do will cost more and perform worse than a new build.

 

How will it cost more? As for performance, that’s subjective based on initial goal of what I’m looking to achieve. I don’t want a passivhouse, enerphit maybe. But still, why demolish a  building that has no real structural fault?
 

20 hours ago, Canski said:

You are not going to get brickwork or blockwork supplied and fitted for those rates. I'm unsure about the other items.

 

Yeah I appreciate that. Should’ve mentioned this was material prices. Labour can be found at whatever rate someone is willing to do it for and you’re prepared to pay. But materials more or less have a trend line so can at the very minimum count on that for estimation purposes.
 

20 hours ago, Redbeard said:

Are you doing all the work yourself? I am not sure where the £40/m2 for EWI came from, even at only 50mm. The '+' must be a very big +! For years 'around £100' has been the regular cry and it very rarely comes in at that. Including 'enabling works I have seen it well over £160/m2.

Yeah, should’ve mentioned I’m looking at materials prices at moment. Hard for a contractor to gauge labour charge. More if stand alone job, but could be less if done as whole package.

 

19 hours ago, Iceverge said:

 

 

 

 

 

Hahahaha. My 2 year old would love option 6 for definite.

 

18 hours ago, joe90 said:

Yes I was thinking knockdown and rebuild properly And get the VAT back.

 

But that would surely cost more? New foundations, cost of demo and clearance? New planning and extra delays? Being that I’ll be paying 5% VAT regardless for everything and 0% VAT for some of the stuff, hardly see the point in knocking it all down to save 5% more? Property has been vacant for 2 years so I get the VAT on the whole refurbishment.

 

18 hours ago, Russell griffiths said:

You are 100% not going to do option 4 or 5 never heard such a ludicrous idea. 
there’s been a few silly ideas on here in the past, but I’m afraid you have just topped them all. 

 

Oh yeah, a proud moment this lol. Tell me then, what was the now 2nd worst idea I just topped? Always wanted to be best in class.
 

16 hours ago, Mike said:

One of these. Which one depends on the state of the pebbledash - in particular evidence of cracking or sounding hollow.

 

However a deep retrofit will be more expensive and time-consuming that rebuiding. Unless you do lots yourself, in which case it may be cheaper but will take much longer...

 

...so give this very serious consideration!

Thanks. As property is empty for 2 years, my entire refurbishment will come in at 5% VAT cost, some items are of course nil rated. Hardly makes sense to knock it down to save further 5% on the tax considering cost of JCB and new foundations. My only issue is the pebbledash, maybe I should just own it? Paint it white, dash showing and all?

 

15 hours ago, Mattg4321 said:

With that much work it’s going to be cheaper and better to knock it down and start again, doing it properly. 

See my comment above to this, the VAT saving is minor, so definitely can’t be cheaper than working with it.

 

15 hours ago, Iceverge said:

@allthatpebbledash, I hope I wasn't poking too much fun with my above post. Sorry if I was. 

 

Practically what you are proposing is possible but very uneconomical. It's been alluded in the above posts that with lots of DIY that it could be cheaper. I made the mistake in our old build of not valuing my time enough. I embarked on circuitous routes because of it and it pretty much burnt me out. 

 

If you really want to avoid a knock and rebuild then I would step back from the bleeding edge of performance a little. 

 

Dig out the ground floor and replace with 300mm EPS. Pour a slab with UFH or float an OSB floor on top. 

 

Suck out the mineral wool in the walls, replace with EPS beads. 

 

Parge internal walls and apply good airtighess to all joists and wall penetrations. Apply a battened internal service cavity with mineral wool insulation. Plasterboard and skim 

 

Install good quality 3g PVC windows and doors.

 

Apply an airtight membrane to the ceiling of the existing roof. Pump 3-400mm of cellulose in there.

 

Install dMEV or ideally dMVHR if possible. 

 

You'll get to about 30kWh/m²/annum like this I reckon and it can be done piecemeal. 

 

Otherwise knock and rebuild. 

Nah absolutely not, I enjoyed the laugh. I recall your previous comments to things I’ve asked regarding retrofitting, I find your input seriously valuable. All the things you’ve mentioned are exactly on the table right now being talked about. This is where the idea of the topic came from lol.

 

Rather than sucking it out, refilling etc. given I want to freshen the facade, taking the outer skin off, use batts, and re skin would be easier and probably more cost effective? 
 

This was the point of the discussion.

 

I think the cost of sucking out the mineral wool, blowing in new graphite EPS beads, hacking off the pebbledash, re point where necessary, then render again is looking to be more costly than carefully sections at a time, remove outer skin, fix batts for insulation, rebuild with fresh brick. 
 

I’ve come across this idea on another forum (PistonHeads) where someone has done exactly this to an old police station. Can post a link if anyone is interested? Their builder did a half wall at a time, the end result is fantastic. Like me, they dislike render too.

 

Anyways, I’m seriously considering this. If anyone is interested, can I post an Instagram handle here for people to follow along?

[crispy_wafer]

Just popping in to say, a neighbour down the road from me refurbed his bungalow last year, roof off, external block and render away, bricked the outer leaf and did an internal refit too and a smallish extension.  Took him 4 - 6 months, but is a builder by trade, so has the benefits of can do, or knows men who can.  

[Canski]

15 minutes ago, allthatpebbledash said:

Oh yeah, a proud moment this lol. Tell me then, what was the now 2nd worst idea I just topped? Always wanted to be best in class.

It may be me. I managed an Oh Lordy Lordy out of him for not fitting MVHR 😂😂

[Russell griffiths]

39 minutes ago, Canski said:

It may be me. I managed an Oh Lordy Lordy out of him for not fitting MVHR 😂😂

Your excused, because I believe you are building them for a profit. 
only so far you need to go. 
I don’t know a single one of my developer mates who fit it, but they are working with a profit margin in sight. 

[gravelld]

Given that the very nature of this forum is that of one for self builders of varying levels of experience, it might be best to describe why something is a "ludicrous idea". Not everyone understands all the steps and risks involved in what turns out to be a complex project.

[Russell griffiths]

@allthatpebbledash I’m just trying to be a realist

your saying a knock down and rebuild will be more expensive, it certainly will be, but how much better will the final product be, and what is the value of a new build versus your refurbishment. 
 

get some nice street scene pictures done for you and get them valued, you might be surprised how much the new build comes out at. 
 

having spent all my life chopping houses about before I found one to knock down, I will never do a refurbishment again. 
 

if it’s been empty two years I can guess what sort of condition it’s in. 
 

 

[Russell griffiths]

What sort of insulation levels would a refurbishment of this kind need to comply with building regs. 
 

if you take down the outer leaf and extend the cavity to get 100mm of batts inside it then what happens with the wall ties, are they not going to be too short, then what about the lintels, then will this wider wall fit on the footings with the new regs on footing width. 

[Canski]

1 hour ago, Russell griffiths said:

Your excused, because I believe you are building them for a profit. 

Oh thanks. I can’t bring myself to build them for a loss. Maybe the same applies to the OP. We all know it would be a better house if demolished and rebuilt but I doubt if the numbers would add up.

[Russell griffiths]

7 minutes ago, Canski said:

Oh thanks. I can’t bring myself to build them for a loss. Maybe the same applies to the OP. We all know it would be a better house if demolished and rebuilt but I doubt if the numbers would add up.

I’m getting far better figures on new builds in the last few years than refurbishing. 
I spent two years doing a complete gut and refit, back to brick everything out, struggled to cover my costs in the end, without drawing any wages on it. 
never again. 
maybe it’s area specific, anything by me old in a good plot is just getting flattened. 

[Iceverge]

I'll reiterate my point buried in my earlier post. 

 

The worse thing that any self builder can do is value their time at zero. 

 

You need to put a £ figure on every hour you spend on site. Say £20. 

 

 

Re taking down the leaf of a cavity wall. @Gus Potter and @saveasteading might be along to discuss why this is a bad idea. 

 

As far as I understand the two leafs when ties together act more like a wide solid wall, like a "H" rugby goals. 

 

When you take away half almost all of the lateral strength disappears. 

[saveasteading]

3 minutes ago, Iceverge said:

@Gus Potter and @saveasteading might be along to discuss why this is a bad idea. 

 

As far as I understand the two leafs when ties together act more like a wide solid wall, like a "H" rugby goals. 

 

Correct. The strength of  a single skin is much less than half of the double skin.  It would need temporary support during the work. THe support gets in the way.

You would not live in the house while this was happening, and should move heavy furniture out.

A new outer skin could be tied using brackets screwed to the inner wall: that is the least of your issues.

 

It's not only structure though.

Do not ignore the detailing at the foundation ( does the widened wall fit on it still?)

Or at the roof. How does this new outer face line work with the current eave and gutter...you probably have to extend the roof at eaves and gable.?

And at doors and windows?

 

I wouldn't dream of doing this. Not with my house and my money anyway.

[Jilly]

On 17/12/2024 at 17:32, Iceverge said:

 

 

 

 

I can’t delete these 😵‍💫