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Testing Quality of Construction Materials

  • 23-11-2021 9:23am
    Registered Users Posts: 520 ✭✭✭

    I watched a recent skillbuilder youtube video about Mica up in Donegal. I'm hoping to build next year. One thing was mentioned is that there may still be products shipping that don't meet standards. I read an Irish Times article that discouraged opting out as the assigned certifier role is meant to address this problem. I'm planning to opt out and use direct labour for budget reasons. That said I'm seriously considering sampling some of the construction materials and sending them to a lab to be tested. Any piece of paper from any professional certifier / supplier isn't going to satisfy me that the products / batch I have onsite is not going to crumble down around me in later years. Plus the whole paper trail is meant to give you someone to go after but wouldn't you rather put that money into verifying that quality materials were used than years dragging someone through the court system? I don't see any self build insurance paying out either!

    There are pro's and con's to either approach I know, but I'm going to start contacting some labs to determine what are the most critical material elements of the build and what tests should be performed on each to give me some indication if I'll have issues in later years or not. That's certainly not done on any building site that I'm aware of any even plants that produce products are only likely to conduct periodic tests and not necessarily the tests that should have been performed for cost reasons etc.

    The Irish Times article mentioned the budget of the local authority to inspect and control this issue and it's not impressive, only allowing targeted inspections.

    Anyway, here's a short list off the top of my head for my house - timber frame, passive raft foundation, block outer leaf, steel beams for large spans:

    Concrete Blocks - test for mica/pyrite content, crush strength, other....

    Concrete in foundation - test for content, slump factor, other.....

    Steel used in beams - tests TBC

    Timber Frame - test moisture content onsite / at point of delivery

    Others: Rebar in foundation, EPS in foundation, posijoists, floor screed, outer render material, roofing membrane, roof tiles, concrete lintels

    (Not all will have viable tests but if they are structural I WANT to know more about the standards they are manufactured to and how this can be proven)

    I'm not planning on going crazy with testing but if I get this wrong I'll be renting for a long time to come. Some measured testing I feel is better than none and may allow me to stop the build to address an issue. I'll need to look at contracts with suppliers to ensure redress if they supply something that doesn't confirm to NSAI standards or at least ask these questions in advance of ordering.



  • Registered Users Posts: 7,983 ✭✭✭Stone Deaf 4evr

    couple of things jump to mind, and to qualify my comments, I've previously worked in a materials testing lab.

    concrete (as in foundations) is generally tested by producing some sample cubes - you have 1 crushed at 7 days to measure its initial strength, and then the remaining one is crushed at 28 days. there is generally a spare kept for 28 days, to act as a control in the event that something is wrong with the first one.

    The caveat here, is the result of the test is highly dependant on the quality of the sample taken, and the cube produced. I've seen 25N concrete test at 60, simply due to the fact that the person taking the sample took due care in making it, removed all bubbles, stored it correctly (wrapped it in moist cloth,after demoulding, then stored it in 20 degree water until tested).

    you can be sure that most concrete workers with experience, will allow the sample to be taken, then add water to the mix to make workability (flow) suit them on site.

    You've mentioned you're going opt out, and direct labour, as you want to save money. When in fact, you're cutting out the very supervision, alongside the use of a reputable builder which might oversee the job correctly.

    The example above is just one item, and I'd query what you intend to do with the information from it. do you stop the build while waiting for the 28 days to pass? by direct labour, you'll be paying up front for materials, so you'll have no comeback to the supplier.