House repairs - your experience and opinion

[Notlbishop]

Hi all, just joined. Was hoping to explain the situation we’re in and whilst i realise its difficult for anyone to be definitive hoping to get your opinions and experiences.

So some context. We live in a 1930s build, semi detached, 3 bedroom.
The building had some remodelling done in the kitchen some time ago before we bought it, a kitchen and diner was made into one room. No regulations were followed and as first time buyers we didn’t ask.

We’ve noticed cracking appear in the kitchen and upstairs in the spare room directly above. This is on the party wall. We know the neighbours had it, not that i’ve seen it but understand it was quite bad. They went through insurers in 2022 and they sent out an independent company, they went through the floorboards, found no signs of subsidence but suggested lateral movement caused by our previous remodelling and fix by stitching using helibars and resin. They sent us the report, i don’t believe they’ve made any fixes recommended.

We noticed the cracks appearing in our kitchen, spareroom and spare room ceiling getting worse, all on the party wall. We brought in builders and SE who uncovered the plaster and found three issues
He did not use steel (sp?) beam to support removal of the wall
He did not use suitable lintel for outside windows
Cracks in the brickwork leading up to spare room.

The first two issues appear to have a ‘simple’ solution and are in hand.
The third one, the cracks is what is concerning. The SE also said there are no other signs of subsidence, the chimney has been inspected, a drain survey also done and came back all good.

The fix has been suggested as also helibars and resin. This is currently underway.

The builder said something today that has knocked us for 6 to be honest. Whilst speaking to him about how they’re getting on he said he has returned to the SE because he believes our mortar is crumbling. He picked up a small section and crushed it in his hand and was very sandy. I asked what this meant and he said it was likely we would see this cracking issue appear elsewhere in the house and the only way to resolve is to demolish the house and rebuild! I know this isn’t covered under our insurance, and we would lose everything. I’ve included photos of the various stages of what’s happened so far.

Have any of you ever come across anything like this before? I think it’s the extremity of saying demolition is the only solution is what has sent us. Obviously very worried. Apologies if the explanation is overlong, i just wanted to provide as much detail as possible. Thanks for reading if you made it this far!

 

[a twig]

Caveated with the fact that I’ve obviously not seen your house etc, from my experience I’d suggest the builder is somewhat going off the deep end there regarding the mortar .

The only time I’ve seen a building have to be demolished due to crumbling mortar was a new school sports hall. They had used one of those big silos for their mortar to ensure consistency etc, the only problem being that it was 100% sand and no cement so a 9m high sports hall was built using concrete blocks and wet sand. Issues started to become apparent within a year with blocks falling out and the whole thing was condemned and demolished.

Given the age of your property and it is still standing - clearly you are not at that level. Raking out and repointing affected areas is a possible remediation for mortar failure if it is indeed failing.

Equally your builder may just be used to modern harder mortars and there might be nothing wrong with your mortar at all.

Ultimately big cracks are caused by movement - if there’s no subsidence then, as the SE has already deduced, it’s likely changes in loading from removing walls etc without appropriate remediation that are causing the cracks.

Getting some steels in should put the load paths back to where they were originally thus stopping the movement and eliminating the causes of the cracks.

 

[stuart45]

How did the bricklayers not realize it wasn't right? I can tell by the colour when the hoddies get the mix slightly too weak as soon as it goes on the board.
I very much doubt the house, or even some of the walls need knocking down. Old mortar is often a bit crumbly. Years of movement tend to break it down a bit. When the walls are plastered, it won't drop out of the joints. It's the sand that gives the mortar it's compressive strength.

 

[Notlbishop]

Thanks both for your time and thoughts. I think I need to see what the SE comes back and says. Regardless i see we’ll need other opinions as there seems to be various ways of interpreting what’s happening. Seems maybe sandy mortar isn’t necessarily the immediate death sentence for the building as yesterdays conversation suggested!

The house otherwise seems to be in good nick, there are hairline cracks in other rooms but nowhere near what we saw in the kitchen. Not sure how long they’ve been there but of course because of what’s happening we’re now seeing them everywhere being more aware and paranoid. There’s a bit of cladding outside that’s fell off around the house at the bottom, small patches in 1 or 2 areas and a big crack in the cladding from the upstairs spare room down to the kitchen which they believe is because the bricks built on top of the double doors to the back garden don’t have a sufficient lintel (they might have said no lintel at all, just a row of vertical bricks sat on the doors that are leaning.)

Still keen to hear others experiences and opinions if they have them.

 

[montyjohn]

Just to repeat what others have said, crumbling mortar does mean a house needs to be rebuilt.

I think 1930's often still used lime, transition period so get a bit confused. But if it is lime it will be very weak compared to cement.
It's a good thing in many ways as it allows the build to move over the seasons with thermal expansion and years of settlement without destroying the bricks.

As the lime wears, it starts falling out of the joints which is when you rake it out and repoint to keep it where it's supposed to be so it can continue to wear.

Your builder is almost certainly overstating the problem here.

Thousands of old building in the UK with very weak lime mortar standing for hundreds of years. You can consider lime mortar weak by design. Just keep on top of repointing as it weathers assuming you have exposed brick and provided nobody knocks out any more wall without support it will be fine like every other building.

This is what I keep telling myself anyway

Top tip. Don't post this on reddit. They will tell you to move out asap for the safety of your family.

 

[Notlbishop]

Just to repeat what others have said, crumbling mortar does mean a house needs to be rebuilt.

I think 1930's often still used lime, transition period so get a bit confused. But if it is lime it will be very weak compared to cement.
It's a good thing in many ways as it allows the build to move over the seasons with thermal expansion and years of settlement without destroying the bricks.

As the lime wears, it starts falling out of the joints which is when you rake it out and repoint to keep it where it's supposed to be so it can continue to wear.

Your builder is almost certainly overstating the problem here.

Thousands of old building in the UK with very weak lime mortar standing for hundreds of years. You can consider lime mortar weak by design. Just keep on top of repointing as it weathers assuming you have exposed brick and provided nobody knocks out any more wall without support it will be fine like every other building.

This is what I keep telling myself anyway

Top tip. Don't post this on reddit. They will tell you to move out asap for the safety of your family.

Thanks and yes, i did go to reddit before i found this site through various searches but don’t like the hysteria there.

I think it is lime. I’m almost sure they’ve mentioned that previously.

The entire house is plastered over, no exposed brickwork at all. So difficult to know what’s truly going on underneath. And definitely no more rework on the structure planned. Just glad to get this one fixed to reg standards. The steel he used to support upstairs was effectively two planks of wood sat on the brickwork. SE was quite disgusted with that, called it shocking.

 

[Stevers]

Getting some steels in should put the load paths back to where they were originally

There will be point loads at the end of the beams that weren't there before, but with pads to start to spread the load these should dissipate down through the bricks to the point where the existing fabric of the building will be able to cope with a marginal extra load - something to 'bear' in mind!

A wall had been removed to build an extension (for a grand piano!) to my parents' house in the 1940s. Although steels were inserted, the extra point load on what had previously been the corner of the house caused some settlement there. This was another 1930s house with a soft lime mortar and in this case diamond hard Verwood bricks, making putting up shelves difficult until SDS drills came along

 

[Flyfisher]

The first house we bought was a 70s-build terrace just out of the 10 year NHBC guarantee. From the outside I noticed that the mortar seemed quite sandy and 'crumbly' such that running a finger along the mortar would dislodge some sand - not much but it still surprised me. It would have been really easy to rake out the brick joints for re-pointing! Anyway, I mentioned this to the surveyor and he said it was fine. When we received the report, it included the sentence "poor but adequate form of construction" - a phrase I've always remembered! But we had no problems with the mortgage and lived there for three years with no structural problems. We also kept in touch with with the buyers for many years (we moved within the same village) and they never mentioned any problems.

I only mention this to suggest that a 'crumbly' mortar alone might not be the source of the problem, especially if the house has been standing with no problems since the 1930s and these problems began appearing after some substantial remodelling.

 

[stuart45]

Crumbly mortar isn't normally a problem, provided it's still in the joints. When it weathers back it's time for repointing. Mortar strengths vary greatly. When labourers on site were shovel gauging, a shovel of damp sand was probably at least double of one of cement out of the cement bag.
Mortar back in the 30's was normally either lime or gauged. Gauged is when around 10% of the total of lime mortar was cement. Cement mortar is virtually unworkable for bricklaying. Later on the mix often used was 1/1/6. It was only when plasticizers came into common use after the war that lime was taken out of the mix. Even with plasticizers a soft building sand is needed to make a workable mortar.
Looking at the photos, the mortar does not look that bad. If it was really weak, you would be less likely to get a large crack in one place, as the wall would move more evenly.

 

[LadyArowana]

The builder said something today that has knocked us for 6 to be honest. Whilst speaking to him about how they’re getting on he said he has returned to the SE because he believes our mortar is crumbling. He picked up a small section and crushed it in his hand and was very sandy. I asked what this meant and he said it was likely we would see this cracking issue appear elsewhere in the house and the only way to resolve is to demolish the house and rebuild! I know this isn’t covered under our insurance, and we would lose everything. I’ve included photos of the various stages of what’s happened so far.

Have any of you ever come across anything like this before? I think it’s the extremity of saying demolition is the only solution is what has sent us. Obviously very worried. Apologies if the explanation is overlong, i just wanted to provide as much detail as possible. Thanks for reading if you made it this far!

First of all do not panic. Whilst I’m no structural engineer there have been some fairly dramatic things posted online which are held up by not much more than hope and wallpaper and if those can be fixed without the need for complete demolition then it strikes me your builder is over egging the pudding quite a lot. Wiser heads than me will be along with reassurance, but in the meantime I would be tempted to look around for another builder.

To put this in context I remember someone online who posted asking for help choosing some French doors/ bifold for the back of his house. He had DIY completely removed a large chunk of what appeared to be a load bearing wall without any props or indeed a plan for some sort of lintel to support the house above. Despite this his house appeared to be in tact, and he became quite cross when people didn’t tell him what sort of doors would look best but instead advised immediate supporting work.

 

[Notlbishop]

Thanks everyone. I have an update of sorts.

They’ve removed the plaster in the upstairs room to start the helibars but have stopped work and have called the SE out. They’re really unhappy with what they’ve found underneath.

The cracks on the left hand side you can fit your hand through and the plaster on the wall on the left has completely come off , i saw him put his hand behind it. Thinks its held on by the coving and skirting board

The diagonal crack from the right to left is what they were expecting to helibar.

The mortar on top row is crumbly, still maintains it shouldn’t be like that, like the cement has dried out. It does show signs of having lime in it somewhere apparently.

Couple of loose bricks in there obviously

Don’t know what to think really. As bad as they’ve ever seen apparently. SE ringing up specifically to ask if the client (me!) were worried.

 

[stuart45]

I've seen a lot worse than that.

 

[Notlbishop]

they’ve left for the day now as waiting for the SE tomoro morning.
Here’s a close up of the bit i think they’re worried about. That’s quite sandy if i rub my finger across it. The rest of the brickwork across is solid no sign of flaking at all as far as i can tell.

I've seen a lot worse than that.

 

[Historic Housesitter]

Hi Notlbishop,

As 'A Twig' mentions, I too have the caveat of not seeing your house in context.

However, I have often visited / worked in 1930's houses, of both lime and cement styles.
To top this, I live in a town with many lime-built houses and have seen many monstrous reno-jobs in my time as painter / decorator / conservation / renovator. To that end, I am also slowly renovating our lime mortar-built Victorian house and we too have taken out a wall between the kitchen and dining room. BUT we have a steel 'T' shaped beam in place, for our extention into the side return. It was also reno'd back in the 80s, where the builders took out all lime plaster and slapped cement plaster both inside and out!

Reading between the lines regarding your builder's take on the lime mortar bed, firstly, with respect, bollox to that! Secondly, it sounds like your builder isn't oh-feh with the special requirements of lime-based properties, so has tried to scare you into believing it's far worse than it is, because he himself wouldn't know where to start or how to treat the job at hand. (Or he's hoping for a big holiday at your expense...) You need the correct builder for the job.

That looks to be sand-and-cement-based plaster on the walls, (exactly the same as ours), which is never a good combination with lime mortared brickwork as it doesnt allow for movement, so will only crack in response.
As context, we have a number of cracks in most of our plastered walls; including between wall and coving - made a bit worse when the downstairs wall was removed and the beam installed - although these were already around most rooms before work started (look remarkably like yours too).
They haven't worsened and when we get to it (winter work lol) the plaster is mostly going to come off, with bags of slaked lime mortar already waiting in the wings.

Science bit:
Slaked / soft lime; which is what your original walls are mortared with, is designed to be softer than the bricks, the idea being that you repair and repoint this, rather than lose bricks to cracks and 'exploded' brickwork due to a hard / cementeous mortar bed. The same lime is used for internal plastering, as well as for external rendering, so is extremely versatile. It comes in three grades 'Coarse', Medium' and 'Fine'.
Coarse is for the mortar bed and also the
1-2 scratch coats applied to brickwork to level any uneveness and give a key for the next coats (horsehair is added to this to aide binding - also healthy urine (IKYN!)
2 coats of Medium for the mid (and top coat if you like the effect - you can stop here) and
1-2 coats of the Fine, which smooths the surface.
Each layer is 3-5mm thick and while curing, needs to be sprayed with water every day to prevent it cracking and drying too fast (modern heating / sunlight etc).
(You can see why builders favour the ease of fast curing cement, which is less than ideal for older houses.)

It is 'self repairing' so you may find by wetting the exposed brickwork, the original lime mortar will regain some strength.
However, bearing in mind that coat of plaster on your walls, the bricks will need repointing, as the plaster will have sapped the moisture from the lime and brickwork, hence the brittle nature of the mortar.

Sounds like the same builders installed the external cladding too... what is it? You haven't said, Is it render or wood or board? I suspect cementeous render? which wouldn't help.

Back to the job at hand...

Can you post a pic or two of the wall and ceiling actually between the kitchen and dining areas?

At this point to be on track with BR guidelines; as others have said, you'll need a steel beam asap. Contact local merchants to visit, quote, create and install one (quotes from three companies if possible...)

- While you wait, buy and install three to four acrow props. (How wide is the K/D room?)

So many outlets out there, you'll have no problem sourcing them. (Definitely buy, don't rent!)

- Get a good solid plank of wood and cut it to the width of the room aperture. Support this with the acrows against the ceiling where the wall was.

By the way, the new cement based mortar used to fix the large crack will just make the bricks crack open instead and the problem will remain, only now you'll have to sort the bricks too, so best it's removed and replaced with the slaked lime I mentioned above.
N.B. The powdered lime bags sold at normal builders' merchants are no good, as they may take a little longer, but harden as much as cement-based mortar. Look up 'slaked lime merchants' on the internet. Delivery charges are expensive depending on where you are based, so a bulk buy is better... They can help you with buying correct amounts of each. In the meantime, YT videos on how to plaster with lime and horsehair.

Lastly, you would definitely do well to 'sack the builder and join the Listed Property Owners Club'!
While you may not own a listed property, it has a great website and magazine, which publishes a directory of much more relevant companies, outlets and specialist craftspeople.

I see you are in Dorset, so it may not be too difficult in sourcing appropriate lime merchants and cheaper delivery costs.

I joined as I work on a lot of older buildings in Kent and I'm forever dealing with mishaps by poorly informed builders and clients.

Good luck and I'll be interested to know how you get on. You may not need the expense of a builder in the end, only the steel beam and installation by the company - and perhaps some nice new tools to do the job yourself!

It's not so hard when you break it down to the sum of its parts and have a wealth of (correct!) knowledge at your fingertips.

EDIT:

I took so long in typing up my post, other posts and photos were posted!
I maintain, the problem is the lack of beam support. Once that is in place - and you are rid of that particular plaster!! - the building will be structurally sound and you will be able to fill all the gaps (with lime!) again. They will be safe, with no more subsidance. As I said, if you use cementeous bond in the cracks, the bricks will crack, not the bond. The reason the plaster on the left is no longer attached is because the wall has shifted behind it and the plaster is made of harder material than the wall itself - I have exactly the same with the render on the external top section of our house.

It truly is amazing how many products are out there that fix one problem but only create another down the line - quick fix money making schemes and not for your benefit, generally. Pardon me, but you are the cash cow and the vultures are circling...!

 

[Notlbishop]

Thank

Hi Notlbishop,

As 'A Twig' mentions, I too have the caveat of not seeing your house in context.

However, I have often visited / worked in 1930's houses, of both lime and cement styles.
To top this, I live in a town with many lime-built houses and have seen many monstrous reno-jobs in my time as painter / decorator / conservation / renovator. To that end, I am also slowly renovating our lime mortar-built Victorian house and we too have taken out a wall between the kitchen and dining room. BUT we have a steel 'T' shaped beam in place, for our extention into the side return. It was also reno'd back in the 80s, where the builders took out all lime plaster and slapped cement plaster both inside and out!

Reading between the lines regarding your builder's take on the lime mortar bed, firstly, with respect, bollox to that! Secondly, it sounds like your builder isn't oh-feh with the special requirements of lime-based properties, so has tried to scare you into believing it's far worse than it is, because he himself wouldn't know where to start or how to treat the job at hand. (Or he's hoping for a big holiday at your expense...) You need the correct builder for the job.

That looks to be sand-and-cement-based plaster on the walls, (exactly the same as ours), which is never a good combination with lime mortared brickwork as it doesnt allow for movement, so will only crack in response.
As context, we have a number of cracks in most of our plastered walls; including between wall and coving - made a bit worse when the downstairs wall was removed and the beam installed - although these were already around most rooms before work started (look remarkably like yours too).
They haven't worsened and when we get to it (winter work lol) the plaster is mostly going to come off, with bags of slaked lime mortar already waiting in the wings.

Science bit:
Slaked / soft lime; which is what your original walls are mortared with, is designed to be softer than the bricks, the idea being that you repair and repoint this, rather than lose bricks to cracks and 'exploded' brickwork due to a hard / cementeous mortar bed. The same lime is used for internal plastering, as well as for external rendering, so is extremely versatile. It comes in three grades 'Coarse', Medium' and 'Fine'.
Coarse is for the mortar bed and also the
1-2 scratch coats applied to brickwork to level any uneveness and give a key for the next coats (horsehair is added to this to aide binding - also healthy urine (IKYN!)
2 coats of Medium for the mid (and top coat if you like the effect - you can stop here) and
1-2 coats of the Fine, which smooths the surface.
Each layer is 3-5mm thick and while curing, needs to be sprayed with water every day to prevent it cracking and drying too fast (modern heating / sunlight etc).
(You can see why builders favour the ease of fast curing cement, which is less than ideal for older houses.)

It is 'self repairing' so you may find by wetting the exposed brickwork, the original lime mortar will regain some strength.
However, bearing in mind that coat of plaster on your walls, the bricks will need repointing, as the plaster will have sapped the moisture from the lime and brickwork, hence the brittle nature of the mortar.

Sounds like the same builders installed the external cladding too... what is it? You haven't said, Is it render or wood or board? I suspect cementeous render? which wouldn't help.

Back to the job at hand...

Can you post a pic or two of the wall and ceiling actually between the kitchen and dining areas?

At this point to be on track with BR guidelines; as others have said, you'll need a steel beam asap. Contact local merchants to visit, quote, create and install one (quotes from three companies if possible...)

- While you wait, buy and install three to four acrow props. (How wide is the K/D room?)

So many outlets out there, you'll have no problem sourcing them. (Definitely buy, don't rent!)

- Get a good solid plank of wood and cut it to the width of the room aperture. Support this with the acrows against the ceiling where the wall was.

By the way, the new cement based mortar used to fix the large crack will just make the bricks crack open instead and the problem will remain, only now you'll have to sort the bricks too, so best it's removed and replaced with the slaked lime I mentioned above.
N.B. The powdered lime bags sold at normal builders' merchants are no good, as they may take a little longer, but harden as much as cement-based mortar. Look up 'slaked lime merchants' on the internet. Delivery charges are expensive depending on where you are based, so a bulk buy is better... They can help you with buying correct amounts of each. In the meantime, YT videos on how to plaster with lime and horsehair.

Lastly, you would definitely do well to 'sack the builder and join the Listed Property Owners Club'!
While you may not own a listed property, it has a great website and magazine, which publishes a directory of much more relevant companies, outlets and specialist craftspeople.

I see you are in Dorset, so it may not be too difficult in sourcing appropiate lime merchants and cheaper delivery costs.

I joined as I work on a lot of older buildings in Kent and I'm forever dealing with mishaps by poorly informed builders and clients.

Good luck and I'll be interested to know how you get on. You may not need the expense of a builder in the end, only the steel beam and installation by the company - and perhaps some nice new tools to do the job yourself!

It's not so hard when you break it down to the sum of its parts and have a wealth of (correct!) knowledge at your fingertips.

Firstly thank you for this considered and thoughtful reply. Going to need to read it 2-3 times more once my head is cleared!

The fix for the steel is in place based on the SE calcs. Added some pics of that in place below

The outside is indeed cement cladding i believe. Another pic added below

He did mention some of the ‘crumbly’ mortar upstairs had horse hair in it for strength so assuming that confirms lime is used somewhere i guess!

I don’t think i will ever be in a position to carry out this work myself. I am a complete amateur, office based and definitely know my own limitations so will defer to the experts and guess will have to pay for my lack of skills and experience!

I was hoping the solution we had was going to fix our problems. Think the realisation is beyond the steel and lintel fixes i guess we’re only at the beginning of the process for the cracks in the wall, starting with a second opinion on a solution tho first i’ll be interested to hear what the SE says tomoro.

Do let me know if any other pics / angles would assist, appreciating that’s the only info point you’re working from.

 

[stuart45]

Once the beams are sorted, the SE might recommend steel angle brackets bolted to the wall in resin. It's a method used on jobs I've worked on where the external wall had pulled away from the party wall because of roof spread. It's quite a common issue on older houses, especially terraced ones.
Can't believe your builder was serious about demolition and a rebuild. Was it his labourer, or the builder himself?

 

[montyjohn]

I'm getting confused by this.
You mentioned your getting steels put in. To me this means RSJs.

But you've sent pictures of what look like new wooden beams.

If these are the original beams that weren't consented then they look good to me provided they are sized correctly (assume this isn't the case as they look new and shiny).

Is it normal to call wooden beams steels?

I assume the SE hasn't specified an RSJ and your builder has put in wooden beams?

I might be being thick here. Wouldn't be the first time.

 

[Notlbishop]

Once the beams are sorted, the SE might recommend steel angle brackets bolted to the wall in resin. It's a method used on jobs I've worked on where the external wall had pulled away from the party wall because of roof spread. It's quite a common issue on older houses, especially terraced ones.
Can't believe your builder was serious about demolition and a rebuild. Was it his labourer, or the builder himself?

It was the main builder. To be fair he used wording - ‘i think’ ‘i’m not sure’ or ‘i don’t know’and his opinion rather than recommending an immediate course of action. He also stopped work until the SE had looked at it.

I’m buoyed that people with experience seem to think there’s a different way to skin the cat with the caveat you’re working from my (probably) poor description and photos.
I’m not sure why he went with the nuclear option as the only option. I did mention repointing but was dismissed as not possible, i wish i had the knowledge to challenge why not, something to do with the gaps i think was said.

It tells me no matter what a second opinion is required. Ideally someone with knowledge of the makeup of these houses.

Thanks again for all your replies

 

[Notlbishop]

I'm getting confused by this.
You mentioned your getting steels put in. To me this means RSJs.

But you've sent pictures of what look like new wooden beams.

If these are the original beams that weren't consented then they look good to me provided they are sized correctly (assume this isn't the case as they look new and shiny).

Is it normal to call wooden beams steels?

I assume the SE hasn't specified an RSJ and your builder has put in wooden beams?

I might be being thick here. Wouldn't be the first time.

There’s someone here who i’m sure will give a better answer than me but i believe the steel is in the centre surrounded by wood

 

[stuart45]

He has used a flitch beam.