Post and beam Posted June 28 Author Posted June 28 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.
Nickfromwales Posted June 28 Posted June 28 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!
Post and beam Posted June 28 Author Posted June 28 '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.
Post and beam Posted June 28 Author Posted June 28 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 1
Kelvin Posted June 29 Posted June 29 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.
JohnMo Posted June 29 Posted June 29 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.
Post and beam Posted June 29 Author Posted June 29 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.
saveasteading Posted June 29 Posted June 29 Doors about windows will do all the air movement you need, in dry weather in June.
JohnMo Posted June 29 Posted June 29 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.
SteamyTea Posted June 29 Posted June 29 The physics of cement cohesion All answers are above. Good luck, it is a technical read.
Post and beam Posted June 29 Author Posted June 29 13 minutes ago, JohnMo said: You said up thread 100 cfm? Can only comment on what is written! Agree totally, my mistake.
Nickfromwales Posted June 29 Posted June 29 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.
Post and beam Posted Wednesday at 21:44 Author Posted Wednesday at 21:44 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. 1
SteamyTea Posted Thursday at 19:27 Posted Thursday at 19:27 21 hours ago, Post and beam said: My tester is unduly pessimistic compared to the others. Did you calibrate yours, I can't remember.
Post and beam Posted Thursday at 19:38 Author Posted Thursday at 19:38 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.
dpmiller Posted yesterday at 05:44 Posted yesterday at 05:44 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.
Post and beam Posted yesterday at 09:01 Author Posted yesterday at 09:01 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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