House Structure Repairs in Manchester from DPS Remedials Limited

Our structural repairs include the following:-

  • CAVITY WALL TIES
  • LATERAL RESTRAINTS
  • CRACK STITCHING
  • FAILED BRICK ARCH REPAIRS
  • LINTEL REPAIR SYSTEMS
  • CORNER CRACK REPAIRS

 

CAVITY WALL TIES

DPS Wall Ties is the specialist wall tie division of DPS Remedials LTD.

 

We are full members of the Wall Tie Installers Federation which means you know your work will be completed by an expert in wall tie installation and you will have the opportunity to have your work independently insurance by the Wall Tie Installers Federation.

 

Our main supplier, Pam Ties LTD, are one of the largest in the country. Working along side them we are able to keep our company current with new innovations in the installation of wall ties and Keep at the forefront of our industry.

 

If you want to understand what wall ties are and the problem with corrosion please read the section below.

 

LATERAL RESTRAINTS

House Structure Repairs Oldham

CRACK STITCHING

Cracked masonry is best stabilised by bonding HeliBar stainless steel bars into appropriate bed joints or cut slots. Tensile loads are redistributed along the masonry to minimise further developments of the crack which may occur with simple injection methods.

 

House Structure Repairs Rochdale

 

Here is an example of one of our crack stitching jobs:

House Structure Repairs Middleton

FAILED BRICK ARCH REPAIRS

 

The load in the brickwork above the arch is distributed and supported by the insertion of helical stainless steel bars. The arch soldiers are then pinned up to the brickwork above preventing them from slipping.

 

House Structure Repairs Chadderton

CORNER CRACK REPAIRS

House Structure Repairs Failsworth

CAVITY WALL TIES EXPLAINED

 

Replacement Wall Ties

Many house buying surveys recommend having the existing wall ties inspected for corrosion, frequently adding that failure of existing wall ties can cause cracking, bowing, or even the collapse of the external leaf.

What Are Wall Ties?

Cavity wall construction originated about the start of the 20th century, although earlier examples are found. The idea is that the air in the cavity itself acts as an insulator, and the cavity protects inside walls from penetrating dampness.

 

Wall Tie Repairs Manchester

 

The internal floors are carried on the inner leaf, as is the weight of the roof. The external leaf protects the inner leaf from thermal extremes, and also acts as a wind shield, absorbing most of the suction and pressure of gusts. To stop any major movement of the relatively slim outer leaf, it needs to be affixed to the more rigid inner leaf. During construction, and depending on the period during which the house was built, a series of wall ties would have been incorporated to form this bond.

 

Wall Tie Repairs Oldham

 

These ties include iron straps, thin 'butterfly' wires, and twisted steel bars, set in to the mortar bed, bridging the cavity from the inner to the outer leaf. Some constructions are designed to have a longer stone set into the wall at set points to act as a connection between the inner and outer leaves.

How Does It All Go Wrong?

Over time, if the mortar in the outer leaf wears away due to weathering and poor maintenance, the moisture allowed in to the mortar joint can corrode the wall tie. The problems caused by this corrosion depend on the type of tie initially installed. The thicker iron strap tie expands as it corrodes, causing the tell-tale cracks in the pointing or render that can be seen outside. Extreme expansion can cause the edge of the roofline to rise, forming a 'pagoda' effect, as the external leaf becomes taller than the internal leaf. Although each tie may only expand by 2-3mm, on a 6m wall this could be a 40-50mm height difference! The thin wire butterfly type corrodes away, but their slimness does not cause forcing of the masonry, or horizontal cracks. This can cause problems in itself, as the structural strength of the ties has gone, but no visible clues exist.

So What's the Treatment?

If it is decided that your ties need replacing, the surveyor will make a decision as to what type of remedial tie to use. This will depend mostly on the type and condition of brickwork. The main types are a mechanical fix, which is either a steel bar with expanding sleeves on each end, or a driven helical bar, or a resin fix which is a threaded, spiral or sleeved bar, with each end set in a resin plug. Some brickwork will require a mix of the types.

 

Wall Tie Repairs Rochdale

 

Too few ties will give an inadequate bond, and too many can make the outer leaf too rigid, and unable to cope with thermal movement or the suction and compression provided by strong winds. Existing ties will be removed if necessary at the same time as new ties are installed (but not before). A good contractor will ensure the joints are re-pointed to match existing, or render repaired. Remember this when comparing quotations. A properly installed and finished job will give you nothing to look at or show off!

 

 

Accreditations

DPS Accreditations