Had a call from a customer to quote for Karndean. She has had two other quotes and not one of them tested the floor. House built in 1968. I know it was compulsury to put a membrane in floors from 1965 but building regs were probably a bit relaxed back then! Anyway there is cheap laminate down and all the joints are swollen, underneath is cheap foam ulay laid on a vapour barrier. Underneath that is Marley tiles. Iv'e managed to get 4 planks up and just tested on search mode with the MMS. It went up to 1000 in all 4 places Now 3 of the areas were dry to touch but 1 was'nt. It seems a very high reading as it's been very dry round these parts ( tested my patio and that read 250) . Thinking they may have a leak. Tested over 20m2 all read a 1000 . What i can't understand is the walls are bone dry . Would it be that the slab has still got room for more moisture before it starts driving it up the walls? Oh i forgot to say i had a plinth off in the kitchen no flooring there and it still read a 1000 but dry to touch. Alot of advice needed on this one i think. Help!!
You have to put a hygro box (or 2+) down on the wettest spots mate, and see exactly what your dealing with tbh Your just guessing otherwise Good thing is, as you have the mms you just need the empty hygro boxes which are about 25 quid a pop and use the mms to take readings You can get high (ish) readings on search mode and still find the readings are below 75rh, but still need to do RH testing to be 100% Def sounds like it wont be straight forward tho
Yeah got hygroboxes mate and the sleeves that you put in the floor. Thing is ive had readings of 240 and they nomally read around 87 percent rh so god knows what 1000 will be!!
mms in scan mode cant tell the difference between condensation and subfloor moister. it may be just surface moister caused by the vapor barrier. With you testing your patio and getting 250 it shows just inaccurate the meter is for testing. The reason why your patio gave you that reading was because the sun would of heated and dried the top few mm of the slab. A little deeper down it will be very wet. Hence so many people can make the mistake of using a meter that is only designed to find the wettest area so you can set up a hygrometer. Also, walls wont be damp unless there is a Bridge in the DPC. A subfloor could have 1" of water over it but the walls will remain Dry. Think about the outside of your house, we could have rain for days on end covering the ground on the outside but your wall's stay dry. Works the other way also, you can have damp walls but a dry concrete floor.
Thing is Matt even under the kitchen units , no flooring at all , it waz reading 1000 and well above dew point. It just concerns me that iv'e never had a reading that high and dont really know how to progress with the job. I dont want to look as though i havent a clue to the customer but really dont know what to suggest. Do you think a leak could be the cause. I'm going round next week to do a proper test but would like to be armed with information . Cheers Matt.
Could be a full rip up sub floor on this one mate. See what the readings are when you go back. Moisture will be trapped under the flooring as its not been breathing. I'd get it all removed then leave it a week then retest it. I would be doing ardex NA, dpm 1c then NA again. Which has worked for me over the last few years.
i dont think a leek but its very possible. With readings as high as you have it does sound like there is no DPM. BUT without setting up a hygrometer you are guessing. Once you have a hygrometer reading , then we can advice. As for DEW point etc, dont confuse this with subfloor moisture. This is the point Relative humidity gives the ratio of how much moisture the air is holding to how much moisture it could hold at a given temperature. As you have no reading of what has been going on in all the time the floor has been down we dont know how much effect this has has and what moisture build up it may be responsible for. Your MMS will work this out for you but only at the given time you are there. If you want to impress your customer you could go into all that tho and do the maths yourself - RH = 100% x (E/Es) where, according to an approximation of the Clausius-Clapeyron equation: E = E0 x exp[(L/Rv) x {(1/T0) - (1/Td)}] and Es = E0 x exp[(L/Rv) x {(1/T0) - (1/T)}] where E0 = 0.611 kPa, (L/Rv) = 5423 K (in Kelvin, over a flat surface of water), T0 = 273 K (Kelvin) and T is temperature (in Kelvin), and Td is dew point temperature (also in Kelvin) So, if you know the temperature, you can solve for Es, and substitute the equation for E into the expression for relative humidity and solve for Td (dewpoint).
Wtf!!!!!! I'm a floorlayer not einstein You been reading a scienentific dictoinary or what!!!! Does sound good though
kelvin is the primary unit of measurement in the physical sciences, but is often used in conjunction with the degree Celsius, which has the same magnitude. Subtracting 273.16 K from the temperature of the triple point of water (0.01 °C) makes absolute zero (0 K) equivalent to −273.15 °C (−459.67 °F). Kelvin is also a friend of mine.
Information overload information overload informaton overload information overload in..................................................................!!!!!!!!!!!!!!!!!!!!!!!!!!
wiki is your friend However, kelvin was part of GCSE's when you did them. Surely they still teach this today in physics ?
