When these types of soils are dry, their volume reduces and it leads to the settlement of the part of the structure. Further, drying of the soil towards the mid of the building is minimal as those areas do not expose to the environment. Therefore, shrinkage mostly occurs at the perimeter of the building. Therefore, these type of brick cracks occurs at the corners of the building. When it dry, it shrinks extensively. When the water added during the drains, it expands.
This expansion lifts the building leading to diagonal cracks in the building. These cracks form due to the uneven stress distribution in the walls. Uneven stress cause due to the reduction area of the wall at the window. As with the above, this will depend on the size of the crack and whether the sill or coping is load-bearing a Structural Engineer will be able to tell you this. In most cases you will need to widen the crack slightly to enable you to insert some mortar compound.
Once widened, mix up some mortar and insert into the crack, pushing the mortar in as far as you can. Once the gap is filled up to the face level it off as flush as you can with the face of the sill or coping stone as this will ensure a natural looking finish. If the crack is quite wide or it is indeed load bearing, a Structural Engineer will be able to recommend the correct repair method. In most cases this will involve stitching as in the repair method for vertical cracks.
Several channels will need to be cut at 90 degrees to the crack and around an inch deep. An Angle Grinder with stone cutting disc will help you. Once channels are cut insert suitable threaded bar or Helical bar and fill with grout or resin.
Again, try and fill as close to the face of the sill or coping stone as possible to ensure a flush finish. If after reading through this project you would like some additional expert assistance and advice, feel free to contact Property Repair Systems as their expert staff will be pleased to give you completely free, no obligation help: All project content written and produced by Mike Edwards , founder of DIY Doctor and industry expert in building technology.
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Skip to primary navigation Skip to main content Skip to primary sidebar Skip to footer Main navigation. Search this website. Blog DIY Competitions. Twitter Facebook Pin It Buffer. Project Page Menu. Settlement cracks in outer cavity wall of property There can be a huge number of different reasons for cracks in the home. Types of Cracks In general, there are two types of larger crack that can appear in the walls of your home that should cause concern.
The direction of the crack should also be noted as this is significant: Horizontal cracks including diagonal or stepped — Usually appear along the mortar joints between brickwork or blockwork. They can follow the mortar joints in a line or diagonally upwards in a staircase pattern. If the crack follows a straight line it is normally caused through applied, sideways pressures e. Additionally, poor drainage issues can also contribute heavily to these issues.
If the crack is running in a staircase pattern across and up a wall then this is normally caused through subsidence or settlement issues causing the foundations to shift. Another possible cause for this is wall tie failure. Wall ties can corrode and expand forcing mortar joints apart and creating cracks. More about this can be read here. In some cases these cracks may also appear in the foundation itself.
Obviously this may be hard to see due to the fact they may be below ground so other, visual effects may need to be adhered to Horizontal settlement crack in wall Vertical cracks —Minor cracks of this type usually tend to appear on internal walls and are the result movement in materials such as plasterboard or brickwork causing the plaster to crack. In the case of major vertical cracks running on exterior walls of your property minimum of 3mm in width this can indicate serious settlement issues or foundation problems.
How Settlement Damage to Foundations Can Happen and Cause Cracks Poor Drainage, Flooding and Rain — Occasionally, if the soil surrounding a property is not properly graded to ensure that any water flows away from the property. Tell—Tale Signs of Serious Settlement Damage Aside from the above types of visual cracking there are a few other, slightly more subtle signs that you could have problems: Internal Doors — When serious subsidence or foundation issues occur they can cause your property to effectively twist and bend.
When this happens, items such as door frames that need to be square so that the actual door fits within it, are pulled out of shape making the door tight and stiff to open and close.
Additionally you may also notice gaps around the door and frame Window Frames — Similar to the above, when a building shifts, things are bent and twisted and the same can be said for window frames. If this happens, windows become stiff to open and close and the glass has been known to crack Nail and Screw Heads — This particular occurrence is sometimes known as nail popping or nail pops. If you have visible cracks, no matter how big, check the area around the crack for any raised nail or screw heads.
Internal stud walls and the plasterboard coverings are pulled apart causing nail and screw heads to pop out. Do not be alarmed if you have a few popped nails round the home, in plasterboard ceilings or walls as this can happen with ordinary, minor movement caused by settlement. But where these popping nails are together with cracks appearing in the wall, it may be time to get the place checked over Settlement crack above door frame Cracks in Walls — are They Still Active? This can be either external or internal.
Repairing Subsidence and Settlement Issues with Foundations In the case of any settlement or subsidence issues this will need to be sorted as soon as possible to prevent any further damage to the property.
Depending on the severity of damage or recommendation of repair from a structural engineer, a fix will more often than not be through one of the two following methods: Slabjacking as an Underpinning Method Sometimes this is referred to as mudjacking or grout pumping. Mass concrete Underpinning Occasionally, when conditions are favourable, a huge holes is dug down alongside the existing foundation.
Piling used as Underpinning This can be done using either concrete or steel piles. Pile and Beam Underpinning Sometimes a pile and beam method is used where piles are drilled down into the ground either side of the foundation very messy inside the home and a concrete or steel beam is pushed under the foundation, or sometimes the brickwork on the foundation, each end of which sites on a pile. Screw Auger Pile and Bracket Underpinning. Piled Raft Underpinning If the entire building needs underpinning and the foundations are very deep, piles can be sunk in a grid, in and around the property.
Mini Piles Through Floor Slab Sometimes the foundations themselves may stay relatively stable but especially in clay soils the compacted ground under the floor slab may drop when it is too dry or the slab has been laid on a sub-base which has not been properly compacted or contains organic material which has decomposed.
Large and Small Cracks in Walls and Foundations and How to Repair Them Once you have repaired the cause of any settlement or subsidence issues using the above information and repair methods, the next job is to repair the visual damage such as cracks and splits in brickwork and blockwork. If the repair of the cause was successful then this may have re-aligned any subsidence issues and actually closed up any splits or cracks but any remaining gaps will need to be strengthened and filled to prevent water ingress or instability: Vertical Cracks The best method for repair for vertical cracks in masonry is to effectively stitch the cracks back together using crack stitching bars.
Horizontal Cracks in Foundations Depending on the cause of the crack will depend on how it is fixed. Again, consult with a professional so that they can diagnose the specific cause of any cracking: Wall Tie Failure — As mentioned above, we have a full and detailed project on how to replace wall ties — this can be seen here Applied Pressures — As mentioned above, these cracks are normally caused through horizontal pressures pushing in on the outsides of walls causing them to bow and separate.
The first type of fix for this issue involves bracing with steel columns or reinforced steel rods that can then be in-filled with concrete blocks that are inserted into the ground to apply a counter-force and stabilise the movement.
Other fixes involve carbon fibre straps that are bonded into the walls that then increase the load strength of the wall and reinforce it. These will not repair the cause of the damage but will stabilise the walls. The final repair method and ultimately the best is to excavate around the outside of the property, removing the cause of the horizontal pressure.
Once excavated, a new exterior wall is constructed against the existing foundation but this new wall will need to be an actual retaining wall with the ability to hold back any soil back-fill and prevent future the same issues happening in the future.
Poor internal Drainage — You will need to check all of your internal plumbing and wastes for leaks and them repaired as soon as possible. This may be a little trickier where pipework that is set in concrete etc…. Faulty external drainage — In terms of external drainage, check that anything that abuts the property soil, pathways etc… is correctly graded and directs water and moisture away from the walls and prevents it from sitting or resting in one place.
The ground floor walls are cavity with I hope you can help! I live on the top floor of an ex-council flat built in the 50s. The building has cavity walls and the windows Hello all, 4 months ago I had the chimney breast removed from both floors, and some sort of metal bracket fitted in that bit of I live in a detached 3 bedroom centrally heated brick house with radiators.
The chimney is on the side of the house which is Ask a tradesman. Like 4. Related Questions Penetrating Damp gable-end wall after loft conversion I live in a s semi-detached house which has recently developed penetrating damp. Blocked air vent - damp in cavity wall? Are the hairline cracks in the wall to do with the chimney breast removal?
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