Thermal movement is a fairly new cause of concern within the construction industry as the use of new modern materials are utilised within construction, the speed of which buildings are erected and the requirement for stronger materials that we can work faster with have been required in the industry as technology has advanced.
Expansion Joints
Thermal movement doesn’t pose serious threat to the structural integrity in the first instance but over time the damage caused can become very serious. Bricks and mortar are extremely strong and able to resist high compressive forces but offers very poor performance when subject to tensile forces.
Thermal movement is basically caused by the expansion and contraction of the fabric of the building due to hot and cold weather. When it’s hot the masonry expands causing compressive forces which the masonry can cope with due to its high compression strength but once it’s cold the material shrinks with tensile forces causing cracking. This cycle is repeated and small cracks eventually turn into large cracks.
Period properties rarely suffer from Thermal movement as many were constructed using soft lime mortars which allow movement slight movement usually accompanying thermal movement.
Cracking Due To Thermal Movement
Modern structures are sometimes built without any expansion joints so the thermal movement cannot be accompanied within the masonry so cracking occurs.
Remedial measures are required in order to prevent further cracking and this should only be carried out by a specialist. Expansion joints are usually a 20mm wide cut which creates a separation in the masonry allowing each panel to accommodate the movement without cracking occurring.
Expansion Joints
Newman’s use the unique Twistfix system which incorporates specialist slip ties and the patented CD drivefix tie combined with a backing cord and flexible mastic creating an expansion joint.
We can guarantee all works for up to ten years and have carried out many projects requiring expansion joints to prevent further cracking.
Bulging walls in period properties are a common defect that are often seen along the gable and flank elevations of a property. This defect is especially common in Edwardian and Victorian properties but is also evident in properties of all ages.
Bowing Wall
Bowing walls should not be regarded as ‘just the way it was built’ this is a serious structural defect that will require a structural repair solution in order to prevent further movement or complete failure.
If the bowing in the wall is only at the levels where the floor joists run either into or alongside then this is more than likely to indicate that lateral movement also known as outward movement has occurred.
Lateral Restraint Tie
Lateral movement occurs when there is no connection between the masonry and the floor joists or stair case allowing the masonry to move independently. In order to prevent further outward movement you must provide a connection between the two.
Newman’s utilise Twistfix lateral restraint ties which are an 8mm stainless steel tie which are installed externally through a 12mm hole in the masonry into the floor joist. With a concealed resin fix to the masonry we are able to tie the masonry to the floor joist which restrains any further movement.
Wall Tie Failure Caused Bowing Walls
In modern properties or buildings constructed with a cavity wall then the bowing if not confined to the floor joist levels only could indicate that there are other structural defects such as wall tie failure which will need to be assessed.
Out lateral restraint schemes for bowing walls can be guaranteed for ten years covered by an IGL insurance backed guarantee. Contact us today if your property is showing signs of outward movement.
One of our first survey’s of the week to this listed property in the high street of Maidenhead, Windsor.
The brick tower is suffering from lintel failure and the flank elevation has bowed and cracked due to lateral movement following the demolition of the neighboring building.
Lintel Failure
The brick lintels will be reinforced using Twistfix helical bars and Twistfix 450mm CD dryfix pinning ties, the lateral movement will be stabilised using Twistfix lateral restraint ties install in to the existing parallel floor joists along the flank elevation.
Lateral Movement
Following the structural repairs the new development works will continue as planned, to find out how we can help with your building and structural repair needs contact our head office on 0333 444 0154 or email us enquiries@newmans.com
