June 28, 20251 yr Author 10 hours ago, Nickfromwales said: But you’ve got to move the air out of the house, not just the room. Its certainly getting out of the house, doors and windows open on the extract side. As i said earlier the fan is moving 100 cfm. That is a large volume of air.
June 28, 20251 yr 2 minutes ago, Post and beam said: Its certainly getting out of the house, doors and windows open on the extract side. As i said earlier the fan is moving 100 cfm. That is a large volume of air. Then tiling before xmas is a distinct possibility sir!
June 28, 20251 yr Author 'the general level of moisture in the house has an impact on the drying speed of the screed. ' agree, which is why i think the volumne of outside air i am blowing through the kitchen should have a lowering effect on the overall RHI %. Remember that my original question was about the fact that the 'meter box' % goes up again over night when the fans are not running. As Nick suggested i think i will lift and move the test box and see if the behaviour changes.
June 28, 20251 yr Author 10 minutes ago, Nickfromwales said: 13 minutes ago, Post and beam said: Then tiling before xmas is a distinct possibility si Thanks Nick. Tiling by early july was the target
June 29, 20251 yr 7 hours ago, Post and beam said: 'the general level of moisture in the house has an impact on the drying speed of the screed. ' agree, which is why i think the volumne of outside air i am blowing through the kitchen should have a lowering effect on the overall RHI %. Remember that my original question was about the fact that the 'meter box' % goes up again over night when the fans are not running. As Nick suggested i think i will lift and move the test box and see if the behaviour changes. Do you think it could be how you’re measuring the RH rather than how dry/wet the floor is. It seems to me that leaving the box stuck to the floor for an extended period of time will allow moisture to build up inside it giving you a false reading. I expect it will read lower if you move the box.
June 29, 20251 yr 8 hours ago, Post and beam said: fan is moving 100 cfm. That is a large volume of air It's not really that big a volume. To put it into perspective, a 200m² house with MVHR would be moving 50% more that 24/7/365.
June 29, 20251 yr Author 37 minutes ago, JohnMo said: To put it into perspective, a 200m² house with MVHR would be moving 50% more that 24/7/365. From the Brink website.... 'The 400 stands for an airflow of 400m³/h' so that would be 100m³ every 15 minutes. I just realised i used the wrong units previously. My fan is moving 100m³/minute.
June 29, 20251 yr You said up thread 100 cfm? Can only comment on what is written! Because your Brink can flow 400m³/h doesn't mean you set to flow that. You set to building regs.
June 29, 20251 yr The physics of cement cohesion All answers are above. Good luck, it is a technical read.
June 29, 20251 yr Author 13 minutes ago, JohnMo said: You said up thread 100 cfm? Can only comment on what is written! Agree totally, my mistake.
June 29, 20251 yr Should be dry by the time we finish discussing it here tbh lol. Move the box about, as I said, to gauge the readings at different locations.
July 16, 20251 yr Author Update. I got my Tiler to bring a pair of his moisture test box's. The procedure for these is exactly the same as mine. Fix to the floor for 24 hours and then 'sniff' the RHI%. No fault with the technique then. Both of these professional level probe style test box's read within 2% of each other but significantly they were at least 20 points lower than mine at 53%!! My tester is unduly pessimistic compared to the others.
July 17, 20251 yr 21 hours ago, Post and beam said: My tester is unduly pessimistic compared to the others. Did you calibrate yours, I can't remember.
July 17, 20251 yr Author 8 minutes ago, SteamyTea said: Did you calibrate yours, No. I bought it brand new a couple of weeks ago for this task alone. Its from Pro Tiler tools. Calibration should not be necessary on a new unit. I'm glad i looked to an alternative device for comparison.
July 18, 20251 yr 10 hours ago, Post and beam said: Calibration should not be necessary on a new unit unless it came with a certificate, this is false- for any equipment.
July 18, 20251 yr Author 3 hours ago, dpmiller said: unless it came with a certificate, this is false- for any equipment. I agree actually when you are dealing with equipment at that level. But a cheap retail humidity sensor is not in the 'calibrated device' arena. Lesson learned for me.
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