Expert Advice

• Whats is Rising Damp
• Guttering
• Roofing
• Timbers
• Wet Rot
• Wall Tiles

What is Rising Damp

Rising Damp is moisture that rises up through materials from the ground surface. Concealing measures, such as attempting to clean the surface or covering up with paint or plaster can actually make the issue worse.

The rising damp contains hygroscopic salts, as dampness evaporates from the surface, the salts remain in the plaster. These then build up which absorb moisture from the air making the problem even worse.

Why does it occur?

Rising Damp may be caused by not having a level of damp proofing in the wall, or by debris bridging the existing damp proof course.

Guttering

We can fit and replace all wood or plastic guttering and attendant piping.

All repairs to guttering and done using state of the art materials which carry a long and effective life.

Gutters and pipes are matched to existing pipe colours.

Roofing

The roof is one of the main reasons why we build houses.

“To put a roof over our heads” and keep out the weather.

Most roofs will last for many decades with little maintenance.

If however, a tile becomes dislodged or broken, then water leaks in and can damage the interior decorations, and fittings, of your home.

Arrange for a periodic check to be done, of your roof, looking for signs of dislodged or cracked tiles, cracking in bitumenised surfaces, interior wet patches, discoloured plaster ceilings etc. All indications that your roof may need repairing or replacing.

Timber

Timber is a living material. It is resilient and long-lasting.

It is used for roofing support, door and window frames, structural strengthening and decorative purposes.

It requires low maintenance and treatment.

It is, however, susceptible to attack from mould, dry and wet rot and insect infestation such as woodworm.

Timber lasts longest when it is kept dry and well ventilated

Wet Rot

Cavity Wall Tiles

Cavity wall constructions originally began in the 19th century, but became more common around the 1900's. The main purpose for building cavity wall type constructions, is to allow the inner wall to remain at a constant temperature whilst at the same time protecting it from the elements of nature.

Original build wall ties were manufactured from a wide range of materials including stone, slate, brick, terracotta, cast iron, wrought iron, mild steel, copper and more recently stainless steel. The most common wall ties manufactured and used today are mild steel, under BS 1243 they are wire ties (butterfly and double triangle) and strip ties (fish tail). The main drawback with steel ties is that they will eventually corrode.

What are cavity wall ties ?

Cavity wall ties were introduced into the construction of the walls in order to tie the inner and outer leafs of the wall together and to add additional strength and wind resistance to the property walls. On the older cavity walls with thicker internal walls the wall ties were introduced during construction in order to give a higher wind resistance to the outer leaf as well as preventing the outer wall from buckling or failing under high wind loads. With later cavity wall constructed buildings the wall ties were designed and introduced so that they would mutually support and transfer the applied lateral and / or vertical loads through to the foundations of a property. If cavity wall ties do not exist then the outer leaf wall may fail under wind loads causing the inner leaf wall to become unstable under vertical loads.

It is important to remember that the wall ties should be flexible enough to allow for the differential movement that occurs between the inner and outer wall leaves by settling and thermal movement. Differential movement generally decreases with time. Within buildings that are 20 years or more it is generally accepted that future movement will be minimal.

How do I know my wall ties have failed ?

The effects of wall tie failure can usually be seen to the exterior of a property by cracking patterns to the render/brickwork, outward bulging of the walls, upward cambering of sills, sagging of lintels and lifting of roof edges. The internal effects however are not as clearly noticeable, but can still be seen by outward bulging (usually at first floor level), separation of the window reveals (usually at first floor level), vertical cracking (external wall to internal wall junctions), separation of floors (from skirting boards and stair stringers), internal finishes and internal cracking.

Upon noticing any of the above symptoms, a qualified surveyor should be instructed to carry out further investigation tests.

Statistics

• Properties built up to 1930's were built with unprotected wall ties.
• Properties built up to 1945 have an unknown tie life expectancy.
• Properties built up to 1964 have an estimated tie life expectancy of 31 - 61 years for strip ties and 15 - 31 years for wire ties.
• Properties built up to 1981 have an estimated tie life expectancy of 23 - 46 years for strip ties and 13 - 26 years for wire ties.
• The 1986 Survey of English Houses published by H M S O indicated that a total of 11.3 million houses were built between 1919 and 1986, and of these an estimated 906,000 now require repairs to the wall structure.

How are wall ties replaced ?

The new cavity wall ties are made from stainless steel and are inserted into the brickwork, through drilled holes, or by removing individual bricks, at set intervals. The new stainless steel wall ties are secured to the inner and outer wall using various methods. The most common methods used are mechanical, cementitious grouting, polyester resin and epoxy resin.

What about the original corroded ties ?

The original cavity wall ties have to be isolated from the outer leaf in order to prevent them from corroding any further and causing more damage. The isolation works are carried out by locating the original wall ties with a specially calibrated metal detector, opening up the mortar joints at the tie location area, and then physically removing or encapsulating the tie ends.