Ian

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Ian last won the day on July 2

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About Ian

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  • About Me
    Chartered Architect
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    North of England

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  1. I'm involved with a largish commercial project which is on site at the moment. The basement was constructed using Amvic ICF using designs by a structural engineer recommended by Amvic (an engineer who is used to their system). Waterproofing of the Amvic was by Sika who designed it (it's a separate membrane system) then regularly inspected the work on site. They are providing a 20 year waterproofing guarantee.
  2. Ian

    Anyone forage mushrooms?

    I've got some nice dry rot fungus on a job I'm involved with at the moment. Ideal growing conditions in a leaky basement so no mushroom fruiting bodies visible but plenty of active hyphae.
  3. @MikeGrahamT21 Not sure if this will help but on my (naturally ventilated and min building regs compliance) timber frame new-build bungalow we got a figure of 3.7m3/(m2·h) on the air test without the use of any specific air tightness products - so no special tape or membranes. We had a ground-bearing concrete floor rather than suspended timber. Anything lower than 3.0 and I would have needed MVHR so 3.7 was a result I was happy with.
  4. I know this is an old thread but for anyone doing a search about propane storage the spare bottles should be kept in a well ventilated and lockable store away from the building or site accommodation. Most people don’t know that propane is heavier than air so any leaking gas has the potential to enter and fill open excavations such as foundation trenches, basements or drains - subsequent risks being the obvious explosion/fire risk but also there’s a suffocation risk due to the propane displacing the air in a confined space such a drain manhole.
  5. @squealeyhealey even in an area of high exposure to driving rain a full-fill 300mm cavity would be okay as long as you use flush tooled joints in the facing masonry wall. Part C of the Building regs guidance only goes up to 150mm full fill cavity but it shows it’s okay with even zone 4 max exposure sites.
  6. They're a clay block very similar to Porotherm. All new Lidl stores are built that way.
  7. Ian

    Paint for concrete floor?

    @reddal Ideally you need an epoxy resin floor eg: https://gbr.sika.com/content/united_kingdom/flooring/en/products-and-systems/resin-flooring/about/sika-resin-flooring.html If you can afford it go for something that has a thickness of between 1 and 2mm. The DIY versions are usually just paint-on and will wear out too quickly.
  8. Intumescent paint expands in a fire and forms a protective layer over the steel that insulated the steel from the heat & flame.
  9. Ian

    Drying of screed

    If you are not trying to stick anything down onto the surface of the screed then getting rid of the laitance is not really an issue although you would still want the surface to be clean and dust free. Your main issue is making sure that the screed is dry enough (it needs to be at 75% RH). There are liquid surface dpm products that can get around the drying issue but they are quite expensive. Alternatively I've occasionally used specialist profiled underlays which allow any free moisture to escape to the edges of the floor.
  10. Ian

    Drying of screed

    You've got 2 main issues that need resolving: ensuring the screed is dry enough (it needs to get down to 75% RH) ensuring the screed is properly prepared ready for the final floor finishes. (If you are planning to stick anything down onto the screed like the bamboo the screed will need the surface laitance removing)
  11. Ian

    Drying of screed

    sand cement screeds and concrete slabs are much more forgiving than anhydrite type screeds and typically need less work to remove laitance prior to tiling. You still need to remove any laitance however there will be a lot less of it compared to anhydrite screeds. The reason for this is that anhydrite screeds contain far more water which is why the laitance is more prevalent. The main issue with power floated slabs is that the power floating process seals the surface of the concrete making the drying process much longer. In fact I would say that 12 months drying time would not be unusual for a power floated slab. The good news is that there are plenty of liquid dpm products that can be applied to the top of the slab to get around this problem however they are not cheap.
  12. Ian

    Drying of screed

    With a click fit type floor you wouldn't need to use adhesive to stick the floor to the screed which makes the while process much simpler however you still need to ensure the screed is properly dry, or alternatively, use one of the special loose underlays that allow any residual moisture to escape to the edges of the floor.
  13. Ian

    Too flat a flat roof?

    @MJNewton It's very common on large commercial buildings that use single ply membrane roofs (membranes like yours) for the membrane to be laid completely flat for example along very long and wide gutter runs (most large new Tesco stores are done that way) so IMO there's absolutely zero chance of your roof leaking due to a slightly shallower angle of fall than the 1:80 recommendation. It sounds like your builder is one in a million! If it were my roof I'd definitely go with option 1. I'd agree with your builder that Option 2 carries a risk of creating unintended damage elsewhere which might mean that you end up with a worse job than the original. Option 3 carries a significant risk of creating a problem with interstitial condensation in the zone between the 2 roof skins.
  14. Ian

    Drying of screed

    advice from BAL is here: https://www.bal-adhesives.com/tiling-onto-calcium-sulfate-anhydrite-screeds/ Edit: Also this advice from Sika: "Calcium Sulphate screeds will not normally start to dry properly until the laitance have been removed. The sooner this process is done the easier it is to eradicate. This is normally the responsibility of the screeding contractor who is best placed to know when the screed has cured sufficiently to proceed. The conditions on site and the thickness of surface laitance play a large part in the drying times that will be required. As a general rule of thumb if the laitance are removed at the end of the 1st week of placing a light sanding action is all that will be needed. In the 2nd week a courser aggregate maybe required. In weeks 3 and 4 you may well require a rotary carborundum stone or a heavy weight diamond grinder. In short, the longer the laitance are left the denser they become and more difficult they are to remove. Once the laitance are removed Calcium Sulphate screeds dry similarly to that of sand/cement, which given the optimum conditions is 1mm per day up to 40mm thick and an additional 2 days per 1mm over this thickness."
  15. You'll have no problems if you just want to switch the pump off for an hour or so while you're sitting outside.