What is a red ash test?
Red Ash (Sulphate bearing hardcore) was used as an infill below concrete floor slabs between 1945 to 1970. CPS can test the level of sulphate within the bearing hardcore, and if necessary can provide a full removal service.
What is a sulphate floor test?
Sulphate floor tests are usually requested by Surveyors when a property is being sold or remortgaged etc. The level of sulphate in the hardcore infill is determined by taking a sample of the hardcore infill from under a floor in the property.
What is a shale test?
Tests used to determine if a specific shale is likely to cause problems include the capillary suction time (CST) test and the linear-swell meter (LSM) test. CST test results show the inhibitive effects of various slats and their concentrations on the dispersion of a shale.
What is sulphate attack concrete floors?
Sulphate attack on ground floor slabs is a very serious problem which can cause structural damage to the main walls of a building. The problem occurs when the fill material (hardcore) beneath the slab contains sulphates and these migrate into the concrete. The sulphates react with the concrete causing it to expand.
How do you know if your house has red ash?
How can you tell? Well it is possible that your floors have ash without any telltale signs, however, those less fortunate will display signs of the floor bulging and becoming uneven. This is due to moisture reacting with the sulphates present in the red ash and causing it to expand.
What is magnesite flooring?
Magnesite flooring consists of Magnesium Oxychloride, which is a white asbestos material. Magnesite was applied to the top of concrete ground floors, which resulted in reddish-pink hued colored floors. Since magnesite is flexible, it is not a suitable material to simply be overlaid by a smoothing compound.
Where does Red Ash come from?
Firstly, red ash is an issue which will be found under your floors. As a byproduct of the pottery manufacturing process, ash (red & black) was used as a cheap and plentiful alternative hardcore when building houses post war.
What does sulphate do to concrete?
Sulfate attack is one of the most damaging causes of concrete deterioration, causing either softening and decay of the concrete matrix (the ‘acid’ type of sulfate attack) or expansive cracking and other disruption associated with the formation of ettringite (calcium sulfoaluminate hydrate) and other reaction products …
Can you build on shale?
In the construction business, shale is an excellent rock to build a foundation on because it’s so strong. Plus, it’s compact enough to endure a structural piling without cracking, unlike clay.
Is sulphate attack covered by insurance?
Sulphate attack is not normally covered by buildings insurance as it tends to be excluded by means of a clause exempting all forms of chemical attack. However, where it is possible to prove that an escape of water such as a cracked drain has triggered the reaction the insurance claim may be successful.
How do you prevent sulphate attacks on concrete?
One of the best methods of preventing sulphate attack is to have the quality of concrete at a low permeability. Also ensure an adequate concrete thickness, high cement content, low water to concrete ratio, and proper compaction and curing. Sulphate resisting cements can also be used to prevent attacks.
What is the problem with Airey houses?
Today the Airey houses are life expired and many are in disrepair. The houses are one of a number of precast concrete systems listed in the Housing Defects Act. This meant that Government help for private owners was available in certain cases.
How much does red ash damage a house?
In extreme cases walls can be damaged as well as a result of structural issues. Unfortunately, red ash was not identified as a problem until the 1970s and no records were kept of how many houses it was used in. Buying a property with red ash which is causing significant damage can typically cost a home owner between £10,000 – £20,000 to rectify.
Are there any companies that do Red Ash testing?
Many companies offering red ash testing are simply jobbing builders who are looking to carry out lucrative floor repairs. They have little, if any, scientific competence- please read this article to see what can happen if you choose the wrong “expert”.
When was red ash used as an infill?
‘Red Ash’ or sulphate damage to concrete floors is very common in areas where mining has previously occurred. Red Ash (Sulphate bearing hardcore) was used as an infill below concrete floor slabs between 1945 to 1970.
Can you test concrete floors for Red Ash?
For almost 20 years we have been testing concrete floors for the presence of red ash. We have an excellent reputation and are regularly used by main lenders, estate agents and the public in general. We offer competitive pricing and will strive to help those who are trying to sell a property where there may be a red ash issue.