Property Repair Systems

Replacing Wall Ties in Cracked, Bulging or Damp Walls

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Summary: How to diagnose wall tie failure and replace wall ties. Faulty wall ties can cause horizontal cracks in brickwork and blockwork as well as bulging and damp walls.

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If you need any help with any type of Wall tie replacement, timber repair, maintenance or other damp problems Property Repair Systems will be pleased to give you completely free, no obligation advice on 01626 336180. The information you need may be in the project below, if not, call them.

Checking and replacing  cavity wall ties. Defects that can occur and some tips for diagnosing and replacing wall ties.

A Borescope, metal detector, surface thermometer and a 'damp meter' (see http://www.dampness-info.co.uk/meters_diydoc.htm) are useful tools for this diagnosis.

Problem: Horizontal cracking in the brickwork, block work or render.

This can indicate wall tie failure, but might also be connected with other types of movement. Consult a qualified Structural Engineer. If the cracks are thought to be a wall tie failure symptom locate the ties with a metal detector and either insert a Borescope through a small, drilled hole (usually 10mm diameter) or remove a brick or block. Check which type of tie you have - a 'fishtail' tie or a twisted wire tie. Fishtail ties can expand enough to cause cracks and must be removed, or isolated, after new ties have been fixed. Twisted wire ties cannot rust enough to cause cracks, so do not require 'isolation' or removal. In either case visible red rust or white rust indicates sufficient corrosion to require replacement.

Remedy: Detect the existing ties with a metal detector, mark out a new diamond pattern and fit replacement ties and then isolate (with a Clan Sleeve, Rockwool or builder's foam) any 'fishtail' ties.

Problem: Bulging of the wall. Danger: walls with bulges can collapse without warning - cordon off and immediately consult a qualified Structural Engineer.

Remedy: If the Engineer considers the bulge to be within the allowable tolerance, fit replacement ties and then isolate (with a  Clan Sleeve, Rockwool or builder's foam) any 'fishtail' ties. Otherwise, the wall will have to be taken down and rebuilt. Sometimes the top triangle of a gable wall bulges because it is single leaf (4.5 inch) - check from inside the roof). Sometimes bulges are due to insufficient tie density - modern standards require at least 2.5 ties per square metre. Detect the existing ties with a metal detector, mark out a new diamond pattern and fit additional ties to meet the Standard.

Problem: Wall construction problems: bricks with holes in them (potted) or with big voids each side (frogged) can be difficult to re-tie with a mechanical expanding type replacement.

Remedy: In these cases you may need to use resin fixing ties.

Checking the tie type: A useful tip - if you do not have access to a Borescope or a Metal Detector you can sometimes view the ties from the cavity using a torch and small mirror, either in the roof space at the top of the wall or by taking out an air brick. This also allows you to measure the cavity width, a dimension needed when ordering remedial ties.

How to calculate wall tie size: Outer wall thickness + cavity width + 55mm

Quick Ties: Easy to install, mechanical fix. Mechanical Tie PN1FX (with unique Shear Nut).

Sizes: Typical - 10mm x 200mm, 10mm x 225mm, 10mm x 250mm

Limitations: Not suitable for bricks with multiple holes, large 'frog' cavities or of very soft material - ask about our Resin fixing Ties for these types of wall construction. Always consult a Structural Engineer, to check the specific wind loadings, wall material densities and other building specific requirements, which may affect the choice of replacement Wall Tie. Once you have this information we will be pleased to assist you with product choice from our wide range of materials.

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The Quick Fix PN101FX double expansion remedial wall ties are manufactured from corrosion resistant Austenetic 304 Grade Stainless Steel tie bars with Neoprene sleeves. The ‘Quick-Fix’ tie features a unique ‘tall-nut’ which when turned with a setting tool, rotates the whole tie bar, forcing the inner leaf Neoprene sleeve to open and grip in the masonry.

The inner fix has now been created. At a factory set torque level, the end of the ‘tall nut’ shears away and the remaining nut is forced down the tie bar to expand the Neoprene sleeve to grip the outer leaf.

NOTE - Don't forget that, if you have existing ties called 'fishtails,' you may need to expose the outer ends of the original ties and 'isolate' them with Rockwool, builder's foam or similar, to prevent future rusting from causing expansion inside the mortar joints and horizontal wall cracking.

As used by the Trade - Quick Ties are inserted into 10mm holes

1. Simple tool tightens inner and outer sleeve

2. Can be driven with an electric screwdriver

3. No resins required
4. Quick to install - just drill & fix

The speed of fix of the ‘Quick-Fix’ tie with a torque set electric drill is probably the fastest currently available in the UK market

How to replace cavity wall ties - Order and Free Technical Help - 01626 336180 - Kathy, David or Angela answers your call - discuss your building problem with a Qualified Dampness Expert (C.R.D.S.)

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