When is concrete\plaster work considered dry?

sas

Hi,

I've been running a dehumidifer non stop for the last 9 days. The rate of water collection has been absolutely consistent during that period.

So I'm wondering if I'm actually making real progress.

Local hire shop carries moisture meters as it turns out. I'm planning on checking plastering and floor screed with this.

However, I know nothing about using these.

If I needed to start tiling in the morning on top of my screed, what level of moisture should I be down to, what effectively constitutes dry is what I'm wondering.

Can anyone please advise?

Thanks

SAS

sas

So I spent half an hour taking readings in the new build this evening.

Comparing the new build to the house we currently live in, the moisture readings are 4 times worse in the new house.

Reading around 5% on the concrete scale of the meter.

The readings did vary wildly though over the walls even with a matter of inches difference in the positioning of the meter.

readytostart

I see you are progressing with your painting and tiling now - What moisture levels did you get down to before you started?
How long did you have to wait after plastering? We've just completed plastering two weeks ago and are trying to figure out timelines...
Did you use the dehumidifier for long and did it cause any cracks?
Thanks

sas

readytostart wrote: »

I see you are progressing with your painting and tiling now - What moisture levels did you get down to before you started?
How long did you have to wait after plastering? We've just completed plastering two weeks ago and are trying to figure out timelines...
Did you use the dehumidifier for long and did it cause any cracks?
Thanks

Science was left out of it in the end i.e. moisture meter wasn't used.

It was about 2 months before we started painting. Tiling was 3 months after floor was poured.

I used the dehumidifiers for too long and caused some cracking at the junction between wall and ceilings. Thankfully this has been repaired and hasn't returned. This was annoying because the plastering was over 6 weeks complete before I brought in the machines.

There is great drying at the moment, I was trying to dry out the house in Dec\Jan.

Every morning when we arrived there was condensation on the windows and in a north facing utility there is a door handle that was always saturated. Once we got to a time when that was no longer happening, I was happy to push on.

readytostart

Thanks SAS
My floor screed is going in next week and the plastering is finished 2 weeks.
The problem is I hoped to move in, in 2 months so i may redo my plans.
The other problem is that I am only down at the house at the weekends so I just leave the windows open 1 notch all the time, which i guess is not ideal for the drying out process. Roll on the good summer weather and long days.

sas

readytostart wrote: »

Thanks SAS
My floor screed is going in next week and the plastering is finished 2 weeks.
The problem is I hoped to move in, in 2 months so i may redo my plans.
The other problem is that I am only down at the house at the weekends so I just leave the windows open 1 notch all the time, which i guess is not ideal for the drying out process. Roll on the good summer weather and long days.

I had a similar problem, I didn't have anyone on site because the house was too wet to push on. With no one on site the windows couldn't be left open fully because there was alot of valuable showers\white goods in the house.

Hence the dehumidifiers and some cracking. 6 weeks after screed was poured and plastering finished, I was pulling 40 litres a day for 2 weeks out of the place.

1 thing I had noticed is that 5 of my windows and my main door (all timber) had swollen and were catching. Now only the door is left to sort itself and it's very close by the feel of it. It's amazing just how much moisture is in a new build.

Patience I'm afraid. It's really REALLY hard to wait but it will dry out.

brendan_donegal

My floors are down about 3 weeks now and plastering finished for 5 weeks and I had windows and doors open all day during the last 2 weeks of really good weather. 2 sets of double doors on south facing side, all floors have changed colour to the dry grey colour they are supposed to be and platering is totally dry now, gone that nice pink colour.

Apart from using a device to measure moisture content (which I don't have), how do I know if everything is dried out properly. Heating won't be on for at least 3-4 weeks. Do I really need to leave for another 4 weeks after that goes on?

And then I have to start tiling, someone mentioned I need to leave the tiles for another 4 weeks to set correctly, seems like a lot of time waiting around, I'm paying rent and mortgage, can't really afford to wait?

Do-more

brendan_donegal wrote: »

, how do I know if everything is dried out properly. Heating won't be on for at least 3-4 weeks. Do I really need to leave for another 4 weeks after that goes on?

It's not very scientific but one way to check for moisture in the floor is to stick down a sq metre of heavy clear polythene sheet in the centre of the floor sealing it well to the slab around the edge.

Check it every day for a few days (that's where it helps if it is clear then you don't have to take it off to check) and if the concrete goes a little darker to the centre of the square then that is the moisture coming up.

I'm sorry to say that concrete takes a long time to dry out.

It depends then on what floor covering you are going to put down. Carpet for example should not be effected by a little moisture coming out of the slab as long as you don't use a rubber underlay, it's wood or laminate you need to worry about.

Last house we built we were walking around on cardboard boxes for 3 months before we laid the wood floor.

brendan_donegal

Thank for the reponse

I'll wait if I need to I just don't want to be waiting around for no reason..!!

Most of the flooring we are putting down is tiles and its a pain because of the adhesive, so i've been told?

kboc

brendan_donegal wrote: »

Thank for the reponse

I'll wait if I need to I just don't want to be waiting around for no reason..!!

Most of the flooring we are putting down is tiles and its a pain because of the adhesive, so i've been told?

concrete floor dries 1mm/day, so 4inch floor (100mm) will take 100 days, roughly!

Do-more

brendan_donegal wrote: »

Most of the flooring we are putting down is tiles and its a pain because of the adhesive, so i've been told?

Get your tiler to talk to the technical service department of some of the major adhesive manufacturers, AFAIK there are some tile adhesives which are more forgiving to higher moisture levels, they will be able to advise on what is best for you to use.

kboc wrote: »

concrete floor dries 1mm/day, so 4inch floor (100mm) will take 100 days, roughly!

That rule of thumb is I believe based on a constant temperature of 20C and a constant R.H. of 60% neither of which are likely to remain constant for 100 days!