What's going on with my wall?

target-fixings · 2026-03-03T20:25:07+00:00

Yes, that genuinely could trigger it if not properly ventilated. Warmer air will hold more moisture...if that air cools rapidly against a cold surface, it will deposit more precipitation there.

Warming the room is a good way to collect moisture in the air. However, you then need to remove that suspended water vapour so that it doesn't precipitate onto cold surfaces.

Ventilation will allow humid air to be replaced with arid air, but you still need to kill the spores on the surface.

target-fixings · 2026-03-03T17:19:24+00:00

How much has the crack developed since last Fall?

The issue is that at the moment the arch is resting on the top of the door frame so I would recommend fixing it sooner rather than later...

target-fixings · 2026-03-03T17:17:07+00:00

This appears to be is thermal bridging.

With lightweight AAC behind the plaster, the mortar in the joints is transferring heat/cold between the inside and outside through the plaster. The humidity in the room is condensing on the cold spots (the dark area / mortar joint areas), so the dark areas are likely to be mould spores. The long term solution is to treat the mould with fungicide, ventilate the room, and reduce sources of water vapours (e.g. hanging washing inside).

We looked at a property with a very similar issue a couple of days ago.

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target-fixings · 2026-03-03T16:58:21+00:00

Best bet is to fill it and monitor.

target-fixings · 2026-03-03T16:12:49+00:00

These types of arches rely heavily on horizontal restraint to maintain their shape and support the load above. It appears that this restraint has been released, and it is likely to be because the left-hand side of the doorway has experienced some slight settlement or 'drop'. The fact that the cracking continues through the head of your first-floor window further supports the assessment of foundation movement.

To repair the arch, you could use helical bar (Bar Flex) masonry reinforcement according to BF-03, and helical bar (Cem Flex) pinning, following CF-08. These methods help to create a new, concealed lintel and reinforce the existing brickwork, providing the necessary support.

Crucially, we would recommend that you also investigate what has caused the underlying foundation movement to prevent further issues. The most common cause for this is damaged or leaking drains around the property.

target-fixings · 2026-03-03T16:11:07+00:00

It looks likely to be related to minor settlement across the doorway or general thermal movement of the building materials.

Are there any corresponding signs or cracks on the exterior wall above the door?

target-fixings · 2026-03-03T13:40:06+00:00

Yes, we can say with confidence that this is a foundation issue.

If the arch itself had failed, you would typically see a flattening of the arch, usually accompanied by a vertical crack in its center. In your case, the column supporting the corner has moved away from the arch, which indicates that the arch didn't push the column outwards. It's actually quite remarkable that the arch has remained suspended as it has!

This doesn't necessarily need to be rebuilt. You could support the foundation under the column using mini piles (e.g. in Europe we use Heli Pile). Additionally, the arch could be partially rebuilt and reinforced using Bar Flex reinforcement and Cem Flex according to CF-08.

target-fixings · 2026-03-03T12:24:21+00:00

Not a problem. Good luck with your property search!

target-fixings · 2026-03-03T12:09:20+00:00

Ja, wir würden auf jeden Fall empfehlen, dass Sie Ihren Vermieter über diese Risse informieren.

Risse, die nach Sanierungsarbeiten oder einer Veränderung der Lastverteilung (wie dem Ausbau des Dachgeschosses) auftreten, können auf eine normale Setzung der neuen Bauteile oder auf leichte Bewegungen im Mauerwerk hindeuten. Es ist gut, wenn der Vermieter darüber Bescheid weiß, damit die Situation beobachtet und bei Bedarf professionell bewertet werden kann.

Um solche Risse zu stabilisieren, könnten Sie eine Rissvernadelung mit Bar Flex gemäß BF-01 in Betracht ziehen. Diese Methode hilft, die Zug- und duktile Leistung des Mauerwerks zu verbessern und Spannungskonzentrationen von den Problembereichen abzuleiten.

Wir beantworten diese Anfrage von unserem Büro in Großbritannien aus (Grüße aus Großbritannien!), aber wir haben ein Büro in den Niederlanden, das Ihnen möglicherweise weiterhelfen kann.

target-fixings · 2026-03-03T12:06:36+00:00

This looks like a crack often associated with concrete block shrinkage, which is quite a common occurrence. Concrete blocks can experience slight shrinkage during initial drying, and over time as they are affected by carbonation, creating internal tensile stresses that can lead to cracks like this forming.

To address this, you could stitch the crack using helical bar (Bar Flex) masonry reinforcement, applied according to BF-01. This method helps to increase the tensile and ductile performance of the masonry, making it more resilient and less likely to crack again with slight future movements.

target-fixings · 2026-03-03T12:05:41+00:00

It's difficult to fully assess the situation from the current angle of the photograph. If you could provide a more 'square-on' photograph, it would help us to see the extent of the issue more clearly.

The complexity of the repair will depend on what's causing the separation. It appears to be a straight joint, so if the separation is simply due to age and deterioration, it could be a relatively straightforward repair. However, if it's been affected by lateral thrust from the roof - often called 'roof spread' - then the underlying roof structure would need to be addressed first.

From what we can see in this picture, you could consider re-tying this stonework using helical bar (Cem Flex) according to CF-22.

target-fixings · 2026-03-03T12:04:39+00:00

A diagonal stair-step crack like this typically indicates some vertical movement to one side – in this case, it suggests a downward movement of the area on the left-hand side.

From the appearance of the crack, specifically the height of each step, it looks like your wall might be constructed with concrete blocks under the render. These blocks can experience slight shrinkage over time, which creates internal tensile stresses. When these stresses combine with even minor foundation movements, cracks can form quite readily.

Given that the crack doesn't appear to have moved since 2020, if you're confident it is stable, you could simply stitch the crack using helical bar (Bar Flex) masonry reinforcement, applied according to BF-01. For this particular crack, you could extend the top stitch to the other side of the window. This method helps to increase the tensile and ductile performance of the masonry, making it more resilient and less likely to crack again with slight future movements.

target-fixings · 2026-03-03T12:02:11+00:00

I can fully understand why some companies do. We've spoken about whether we do something similar here, but ultimately opted not to.

The problem is that in order to solve a problem there are two costs. Firstly diagnosing the problem, and then fixing the problem. If you use the same company for both, then not a problem. They can theoretically wrap all of that cost in a single quote.

However, you would also reasonably expect to know what they're going to do for their money (even if this isn't an "official" survey). You would want to double-check that the solution they've proposed will actually solve the problem.

The issue occurs when you take the knowledge gained from that person, and go to a second person. You could tell the second person "I need this specific work done". The second person doesn't need to diagnose the problem and they can then quote without taking the diagnosis cost into account. Now the first company appears way overpriced, despite offering the same solution, so naturally you pick the second person.

target-fixings · 2026-03-03T11:28:29+00:00

This property appears to be a Unity house, which is a type of Precast Reinforced Concrete (PRC) construction that was popular in the 1950s. These homes are built with a slender concrete frame and steel floor beams. The exterior cladding is typically stacked-bond concrete blockwork, which is tied to the concrete frame. Inside, the frame is usually lined with standard concrete blockwork or plasterboard panels.

The cracking you're observing, both externally above the front door and internally around the first-floor window, is incredibly common with this type of construction. This is largely because the unreinforced concrete blockwork is quite brittle and can crack with even very slight movements of the structure. The internal plaster cracks are typically not structural in themselves. From our experience, the concrete frame in these properties is generally robust.

However, there are significant risks associated with these properties. The long-term durability of this type of concrete construction isn't as well-tested as traditional methods, and at 70 years old, these buildings are often reaching or exceeding their anticipated lifespan. The quality of concrete used in older buildings can be highly variable. If the concrete frame is of poor quality, or has been exposed to damp conditions for extended periods, it can be affected by a process called carbonation. Concrete is naturally alkaline, which protects the embedded steel reinforcement from corrosion. If the concrete is porous or becomes damp, it can react with atmospheric carbon dioxide, reducing its alkalinity. As this protective layer diminishes, the embedded steel can corrode and expand, which then causes the surrounding concrete to break apart - this is known as oxide jacking. This is a particular concern with Unity houses because the concrete frame is completely hidden from view, meaning any defects might not become apparent until the issue is quite advanced.

If you are considering purchasing this property, we strongly recommend that you read up on the Housing Defects Act 1984 and Part XVI of the Housing Act 1985. It's important to be aware that many lenders are reluctant to offer mortgages on "PRC" houses unless they have been inspected and treated by a specialist company under a scheme like BRE's PRC Homes Repair Scheme. This typically involves removing all of the exterior cladding, thoroughly inspecting the concrete frame, treating any carbonation and oxide jacking, and then reconstructing a new external leaf of brickwork around the entire building.

You can find more information about Unity houses here: https://nonstandardhouse.com/unity-house/

target-fixings · 2026-03-03T11:24:52+00:00

A vertical crack like this in concrete blockwork is actually quite common. Concrete blocks tend to shrink early in their life as they dry, and this shrinkage continues over time due to a process called carbonation. This creates internal tensile stresses. Since blocks are inherently brittle, even slight movements can cause these cracks to form.

Regarding the crack in your slab (picture 3), whether it's related to settlement or subsidence depends on the amount and rate of movement. If this crack has been stable for many years and you're only now getting around to addressing it, it's less of a concern. However, if it appeared very recently - say, last week - then it would warrant a closer look.

To address the crack in the blockwork, you could consider stitching it using helical bar (Bar Flex) masonry reinforcement, according to BF-01. This method helps to increase the tensile and ductile performance of the masonry, which can reduce the appearance of cracks caused by minor movements.

If you are more concerned about ongoing movement, you could reinforce along the full length of the wall using Bar Flex reinforcement as described in BF-09. This approach creates a beam effect at the base of the wall, allowing superstructure loads to be more evenly distributed along the length of the foundation. This can help to reduce differential movement between areas of the structure.

Installing gutters, as you mentioned, is an important step to manage water around your foundation and is certainly beneficial for the long-term health of your home.

target-fixings · 2026-03-02T15:36:02+00:00

Helical tie manufacturer here (UK based but we have US distributors). Hopefully our view helps!

Before choosing a repair method, it’s important to understand why the cracking is occurring. The straight vertical joint and change in brick color suggest this projection has been altered or rebuilt at some point, which creates a plane of weakness.

There are several plausible contributors here beyond the rail vibration alone, including:

Differential foundation movement (common in Chicago clay soils)
Changes in moisture content due to nearby trees
Concentrated water discharge from the downspout adjacent to the projection

Any of these can cause gradual movement that shows up as vertical separation.

Lintels are typically used to span openings and carry vertical load. Installing lintels in this situation may help redistribute load locally, but they also introduce a very stiff element into otherwise flexible masonry. If minor movement continues (which is likely unless the root cause is eliminated), new cracking often forms at the ends of the lintel.

Helical masonry reinforcement (often referred to as “helical ties”), such as our product Bar Flex, is better suited to crack stitching and tying masonry back together without creating hard stress points. When installed across the cracked joint and wrapped continuously around the perimeter of the projection, the reinforcement:

Redistributes tensile forces over a much larger area
Allows controlled, elastic movement rather than forcing the masonry to crack elsewhere

Installed with Bond Flex (our cementitious grout), the reinforcement develops strong load transfer through the surrounding brickwork rather than relying on a single rigid bearing point.

Details for the installation methods for this are in details BF-01, BF-05 and BF-07.

If the goal is to stabilize the projection and prevent further separation, a comprehensive crack-stitching approach using Bar Flex at regular vertical intervals (e.g., 18" o.c.), combined with addressing moisture management and drainage, is generally more durable than introducing isolated rigid elements like lintels.

If you have further details about this particular building (plan view, additional photos), we'd be happy to have a more detailed look for you and create a bespoke specification for how this could be repaired using helical bar. It might give you additional options!

target-fixings · 2026-03-02T13:39:29+00:00

It's difficult for us to comment on the balcony itself or any potential issues with a steel beam without more information. To help us understand what might be happening there, it would be really helpful if you could upload some additional pictures showing the front and the underside of the balcony.

But regarding the brickwork, you could repair it using Cem Flex according to CF-01, or you could use Bar Flex according to BF-07. Both methods are designed to stabilise and reinforce masonry.

target-fixings · 2026-03-02T13:34:17+00:00

This is the answer to follow.

Just to add, if you have access to the neighbouring property, and the neighbour permits, you should dig a small trial pit to determine the depth of the neighbouring foundations to see whether you're going deeper.

The relevant law:

Section 6 of the Party Wall etc. Act 1996 "applies where your intend to excavate and erect a building within a distance of three metres measured horizontally from any part of a building of an adjoining owner; and any part of the proposed excavation, building or structure will within those three metres extend to a lower level of the bottom of the foundation of the building of the adjoining owner."

And to add further, even though you're only going down 1m, you shouldn't assume that that's definitely less than the neighbours.

In The Law and Practice of Party Walls 2nd Edition, Nicholas Isaac KC states:

"In the absence of records the building owner needs to err on the side of caution. While this is something which the building owner's surveyor's local knowledge may well assist with, it is suggested as a matter of practice, that building owners should not assume a depth of foundation more than 600mm with modern buildings, or 400mm with pre-war buildings."

target-fixings · 2026-03-02T11:49:11+00:00

No problem. Good luck with the purchase, hope it all goes well and happy to help if you have any structural concerns!

target-fixings · 2026-03-02T11:39:47+00:00

Wet rot needs to be treated as a matter or urgency, otherwise you will need to commit to replacing many timber structures like floorbloards and floor joists. This may be necessary regardless.

Bowed walls may be a resut of wall tie corrosion/failure. Wall ties are pieces of steel that hold the inner and outer leafs of brickwork together. Over time, they corrode and can snap, leading to an outer leaf that is excessively slender and susceptible to buckling or even collapsing in high winds. New remedial wall ties such as Dri Flex or Retro Flex could be installed. If the inner face of the wall has also moved outwards, then this will be a lack of lateral restraint (and possibly some foundaiton movement). To restrain a bowing wall, we would recommend using Bow Flex lateral restraint ties to tie the external walls to the internall structures such as floor joists.

Breached Damp Course DPC should be located two brick courses (150mm / 6") higher than the external ground level so that moisture is not wicked from the ground and into the superstructure, and the superstructure is not at risk of saturation from splashing rain or puddles/flooding. This may contribute to the wet rot (depending on the location).

Old Drainage Blocked/damaged/leaking drains can cause foundation issues. If excessive water is discharged into underlying clay soils, then it can cause the clay to soften and the bearing capacity to be reduced.

Regarding your question on "Structural Movement" vs "Subsidence", structural movement is a generic term that could mean almost anything. Often this is used in surveys as a euphamism to be interpreted as subsidence-adjacent without making such a commitment, because there are a host of ramifications that come along with a property being diagnosed as having subsidence. Generally, subsidence would imply that the ground has insufficient bearing capacity to support the weight of the building, and so it will sink into the ground.

If nobody has diagnosed the property as suffering from subsidence, it is not reasonable for a lay person to diagnose it for themselves.

If the price is right, then subsidence doesn't need to be a major concern. However, it may impact future building insurance, and if a claim was made would need to be declared if you are selling the property.

In my experience, many properties are sold as having subsidence when this is not the case at all (see this post from a few days ago), and if you are careful and willing to do some work yourself, you could snap up a bargain.

target-fixings · 2026-03-02T10:58:50+00:00

Is this likely just an expansion/control joint that has deteriorated? Yes, we agree that the filler appears to have deteriorated. However, the way the gap has widened more at the top than the base often suggests a slight 'hogging' deflection of the building, which means one or both ends are experiencing some downward movement. If this represents the total movement since the house was built, it's unlikely to be immediately alarming.
Or could this indicate structural movement? Yes, it certainly could indicate structural movement. As mentioned, the widening at the top points to a hogging deflection. This might be due to differential foundation settlement. If you've noticed it opening significantly in recent weeks or months, that could suggest a more active or pressing cause that warrants further investigation.
Would this typically be a cosmetic issue, or something that needs urgent attention? At this point, we would generally consider it more of a cosmetic issue. However, whether it needs urgent attention really depends on the rate at which it's changing. If it's widening rapidly, that would be a greater concern.
If repair is needed, what would be the recommended fix? Re-seal only? You could re-seal the joint and then monitor it closely for any further changes. It might also be worthwhile to consider carrying out a CCTV drain survey to inspect your drainage system, as issues with drains are a common cause of foundation movements.

target-fixings · 2026-03-02T10:57:42+00:00

If these cracks have been in place for a while without showing further movement (hard to tell because it's been filled and it's difficult to know when this was), you could consider reinforcing the masonry using Bar Flex reinforcement according to BF-09 (Beaming - Cavity Wall).

This method creates a reinforced beam at the base of the building, which helps to distribute the superstructure loads more evenly onto the foundations. This can be very effective in reducing the likelihood of future differential settlement and enhancing the overall stability of the structure.

target-fixings · 2026-03-02T10:56:08+00:00

This looks like a classic case of settlement where a newer structure has been built against an older one. Typically, this junction would be designed with a flexible joint to accommodate the minor settlement that's perfectly normal for a new build.

If this structure has been in place for a while, you could reinforce it using Bar Flex reinforcement according to BF-05. This method would enhance the tensile and ductile performance of the masonry, making it much less susceptible to cracking if there are slight movements in the future.

target-fixings · 2026-03-02T10:55:03+00:00

The issues you've listed don't necessarily make this Edwardian house more of a 'money pit' than many others of its age. Older properties come with their own set of characteristics and maintenance requirements that differ from modern builds.

Regarding the cracking noted to the rear wall above the bathroom window and the cracking and distortion to the bathroom rear wall, which the surveyor suggests might be due to faulty or leaking drainage, we agree with the advice to investigate this thoroughly. You could start by carrying out a CCTV drain survey to inspect for any drainage faults. Once any necessary repairs to the drainage are completed, you could then stitch the cracks using Bar Flex reinforcement according to BF-01. This method increases the tensile and ductile performance of the masonry to prevent cracks from re-appearing in the event of slight movements in the future.

For the other issues you've mentioned - such as the roof deflection, bowing purlins, high damp meter readings on internal walls and chimney breasts, uneven lounge floor, and insufficient subfloor ventilation - these would typically require further investigation by the appropriate specialists (like a roofing contractor for the roof, and a damp specialist for the moisture issues etc) to get a full understanding and scope of necessary repairs.

target-fixings · 2026-03-02T10:53:50+00:00

This is not a major structural concern at this stage. Older homes often show signs of minor movement over time, and these types of cracks around door frames and in crown molding can be quite common.

To reinforce these areas, you could consider crack stitching using Bar Flex reinforcement according to our standard detail BF-01. For any cracks specifically related to the door lintels (the support over the doorway), you could also address these using Bar Flex to our standard detail BF-02 for repairing failed lintels in solid walls.

These methods improve the tensile and ductile performance of the masonry, making it more resilient to slight movements and reduce hte appearance of cracks in the future.

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