Small hairline cracks in exterior house walls usually don’t cause major structural issues and can usually be easily sealed, although that has to be done correctly or the cracks will reappear.
However, larger cracks may indicate serious structural issues and require immediate attention.
Render not only protects walls against weathering, but it also adds a protective layer to the brickwork that shields it from wind-driven rain or changing temperatures.
If this layer becomes compromised due to hairline cracks, water ingress and dampness will become greater threats.
What are cracks in walls?
Hairline cracks in rendered walls are an unfortunately common occurrence that can be easily remedied.
Your home’s structure will naturally move with changes in temperature and humidity, leading to slight expansion and contraction of the exterior rendering.
Cosmetic cracks are usually minor and can be remedied with some new render.
Hairline cracks in painted walls may sometimes be harder to discover as some doofus has painted straight over the cracks instead of repairing them. You may only discover the cracks once you remove the paint on your wall.
Do NOT use silicone mastic to repair a hairline crack.
Yes it may “seal” the crack, but it is temporary and the mastic will shrink and the crack will open up again. That is the “cowboy builder” way of doing it and you should avoid that.
However, if the crack is extensive and extends across your wall, it might be time for you to call in an expert to assess the issue.
A wall crack that is accompanied by a horizontal gap could be indicative of subsidence, or when the ground beneath your house begins to shift and sink, leaving your home and foundation unsupported.
There are various reasons why this might occur, such as insecure ground conditions, movement caused by tree root growth, or worst case scenario, concrete cancer.
Furthermore, you need to assess any underlying structural issues like foundation shifting that need professional intervention for resolution.
What causes cracks in walls?
When a new house settles or the construction materials expand and contract, walls may develop cracks. These are normal and can usually be remedied quickly and cost effectively.
Assessing the seriousness of wall cracks requires tracking down their cause or causes, as well as monitoring them over time.
Some cracks are purely aesthetic in nature and can be remedied with re-taping and painting.
Other cracks could indicate a more serious underlying issue, such as subsidence, inadequate initial design or structural and foundational problems.
These cracks should be investigated promptly by a certified building inspector or structural engineer to guarantee your property remains secure for you and your family members.
Hairline cracks in rendered or pebbledashed walls are a common occurrence and usually indicate shrinkage due to seasonal climate changes.
Other horizontal cracks observed during a building inspection could be signs of unbalanced soil pressure on concrete block base walls, suggesting potential load bearing issues.
How to repair all kinds of cracks in walls
Even the best-built houses eventually develop cracks around doors and windows due to settlement.
Cracks are not something to be ignored, they won’t go away over time, in fact they will get worse over time and cause your render or pebbledash to crack, allowing water into the wall coating, which freezes in winter and pushes away the surface coating.
This is known as “blown render”
Hairline cracks in rendered walls are not uncommon and can often indicate structural issues.
If they’re accompanied by popping nails or screws, leaning or bowing of the walls, and/or twisting or tilting of the building itself, these can be hazardous for your health and safety.
Rendering is intended to shield underlying brickwork from weathering, yet it can still crack over time due to water evaporating too quickly or lack of time for the render system to bond properly with the wall.
Changes in soil moisture content can also cause subsidence and cracking, either from rainfall or extended dry spells.
Vegetation roots may absorb moisture from the ground, altering its moisture balance.
The method of repairing cracks properly.
The correct way to repair a hairline crack is, using an angle grinder, cut out the crack, make it wider, into a “V” profile.
Then using a dry paint brush, sweep away all the dust in the crack.
Then using the same paint brush, paint a mixture of PVA Unibond and water on the whole length of the crack.
Using a trowel, apply mortar into the crack, and smooth out flush to the wall.
Once the mortar starts to dry, use a plasterers float, wet it, and smooth the mortar out further using circular motions on the wall.
Then take a sponge, make it moist rather than wet, and smooth out the new mortar over the crack, again using a circular motion.
Then repaint the wall and hey presto your crack has gone!
Bear in mind that cracks can allow water into the wall, so while you are working on the house, use a hammer or cold chisel and tap the render around the cracks. If it makes a hollow sound, the render is blown and must be replaced.
The National house building council has the following guidance related to cracks.
Cracking in the home
Most homes will experience cracking at some point, no matter how well-designed or
built they are. The cracks are not normally serious and are very unlikely to affect the
stability of the building.
What causes cracking?
There are a number of reasons why cracking can occur, but it’s most likely to be because of drying shrinkage, thermal or moisture changes in building materials, or ground settlement.
Shrinkage
Shrinkage occurs during the initial drying out of a home.
Many of the materials used to build a home (such as mortar, plaster and concrete) contain a lot of water when they are built-in and can shrink as they dry out.
This may lead to some minor cracks in walls and floors as your new home fully dries out over
several months after you move in.
Source: nhbc.co.uk
So cracks can still occur in newly built homes as well as older houses.
How to prevent cracks from coming back to haunt you.
Water-repellent exterior wall coatings are an effective solution to prevent future hairline cracks from occurring.
This wall coating bonds with the underlying render, providing additional protection that reduces water ingress risks and keeps your rendered walls free from dirt and grime accumulation.
Exterior wall coatings are available in a variety of pleasing colours, plus transparent too, which the latter is ideal on listed buildings, and on homes where the owners want complete weather protection but wish to keep the property looking exactly as it is.
The coloured wall coating system lasts for over 2 decades, stops damp, and is guaranteed to not to fade, crack, chip or peel.
All repairs are done by our expert teams prior to the application, by spray, of the wall coating.
Such repairs commonly include: Damp proofing, re-rendering or patch repairs to render, replacing loose or missing brick pointing, repairing cracks, re-texturing pebbledash, and so on.
All our wall coatings do not crack, and remain fully flexible on your walls, so no more crack repairs and no more cracked walls.
Once we finish the wall coating job, usually less than a week, your home will not only look it’s absolute best, but will be fully watertight, weatherproof and free of any repairing or maintenance for the next 20 years.
Contact us today to find out more about wall coatings for your home.
You can call us FREE Monday to Saturday, on 0800 970 4928
You can also send the team an email with your requirements.
We look forward to hearing from you.
Alex.
PS we do NOT offer a crack repair service, we are not a handyman service, we repair cracks as PART of our exterior wall coating service. Thank you