[martin19842]

hi there,

has anybody got a control value, for %WME and relative humidity level for block and beam floors, and dry lined walls.

We are taking control measurements from the plot next door, the development only being 14months old, and the developer is going to provide figures from their records.

But want to see if they match our levels.  It has been suggested that we are looking for a 30% rh level.

Any opinions greatfully received.

and it looks like we have got another flood job out of this aswell.

regards

Martin

[John Kelly]

Hi Martin

How are you measuring these. What meter are you using. I take it these are new build, if so it is likely there was still some construction moisture. Anything under 70%ERH would be satisfactory.

[martin19842]

hi john

we will be using a protimeter mms+

the house has been lived in for 14 months.

and therefore using the protimeter we will take rf readings for the walls and floors. of the neighbouring plot.

and we will then use sleeves and drill the slab, to take the readings in the plot that we are dealing with.

one of the issues on the slab, is that laminate, is to be relaid.

we lost the kitchen ceiling last night, as it had blown, and cracked during drying.

thanks for your input

regards

martin

[martin19842]

john,

is your tramex meter, a match to the protimeter mms.

might be interested in one.

regards

martin

[John Kelly]

Hi Martin

ERH of 65% will be fine for relaying laminate. I usually use a Protimeter humidity box on the slab sealed with blue tack and a weight on top. This needs to be left in place for at least 3 days to comply with British Standards. Failing that a square of thick polythene taped down with duck tape does the trick. Leave it in place for 3 days then make a small nick in it with a stanley blade, insert your MMS probe and it will give you a good ERH reading. You can usually tell if its still damp as there will be condensation under the polythene.
Search mode on the plaster board is ok, I usually accept anything under 200. Don't forget your studs, the boards could be dry but the underlying timber work could be damp. 2 pin probes or humidity probe into void will do it.

The Tramex is a good robust bit of kit for the price. I have just sold one to a Chem-Dry guy and he does not like it as much as his MMS. I like it and it is nearly half the price.

[martin19842]

hi john

thanks for that,

what would you recommend the hygrosticks or the humisticks? on the mms

yes the slab is already sweating as we are heating the ground floor rooms up.

i am enjoying it though, ive the electricians in tomorrow to wire a temp supply, they wouldnt touch it last week.  so weve got all the sockets, switches and ceiling roses, opened up.

everything is being run from multi phase generator at the moment.

see where we are with it a few more weeks down the line.

regards

martin

[John Kelly]

I have only ever used the Hygrostick as the Humistick is only for models manufactured after October 2005.

[DP]

Martin
Are you carrying out the drying or just monitoring?

[martin19842]

hi dp,

we are doing the drying and monitoring,

we are cooking on gas now, power and heating re-instated all dehums, and fans up and running.

all ceilings taken down, and wet and damaged contents removed and disposed of.

Now we just sit and wait.

regards

martin

[DP]

Martin
Just wondered and without knowing the extent of your knowledge base on this subject but localised RH readings will tell you very little about how dry anything is on their own.

Ill take the plunge and offer some advice (which you may or may not already know, no doubt you will tell me and if you do then it was a simple gesture which I’m sure you wont mind.

Plaster boards constructed on any framework should dry very quickly (with the exception of any floor contact). If they don’t then you are likely to still have a source within the cavity, ie wet insulation or saturated building fabric (brick, block etc).
 
In this instance the cavity will need to breath which can be achieved by making a number of holes along the skirting line and again close to ceiling level or first line of noggins. Better still is to introduce an airflow into the cavity via an air mover, if you don’t have a snout kit simply make a number of slightly larger holes and point the air mover at them leaving a gap of about 6 inches to allow for back pressure. Wet air from the cavity will then escape via the top holes into the room or via an external vent to the outside. There is often drying time constraints with gypsum as it can produce mould very quickly.

This is a massive subject and one I have spent 25 years in, however I am sure you have it all in hand. Just a little anxious about the RH and ERH thing.

   

[martin19842]

dp,

thank you very much for the info,

we will next week start to take deep probe readings for the developer. this was always the plan.

the surface of the boarding is drying, and the flood was clean water and not black water.

several of the walls are open, as we have the ceilings down.

i totally agree, with you about ventilation, and the floor contact of walls.

obviously we dont want to pull the place apart totally, but there is a balance between drying time, mould and refurbishment costs.

I must say this is the largest one that we have done, and i do love it.

regards

martin

[DP]

The hang up will come when the drying time start exceeding value in respect of drying costs. Should you start getting this kind of feedback, I can advise you how to force dry the floor in half the time (which you may already know) but if you dont then I am happy to advise. Problem will be that the developer might ask why you didnt do that in the first place, so have an answer ready.

[martin19842]

dp,

i have emailed you, thanks

regards

martin

[martin19842]

well the email bounced back to me, so


hi there

the floor is block and beam, as we have heated the house the slab has
started to sweat.

the whole house is nice and warm now, and the de hums working away, along
with airmovers.

so any advice about the floor would be appreciated.  this being the longest
duration of the drying process.

regards

martin

[DP]

Seems the server is down again. Got to run just now,but will be up again a little later.
DP

[John Kelly]

Martin

Your concrete should dry our at around 3mm per day if you have below 40rh and around 20c.
As mentioned earlier your ERH of the slab is the interface between the slab and surface air. This is what determines whether any flooring will absorb moisture which could lead to swelling and possible mould problems. As I said anything under 65% will be safe to re-lay laminate.

[jasonl]

sounds like you need some serious kit    www.scirocco-services.com   a regular house would be dry guaranteed in 5-7 days at the very most,  in Carlisle last year 2 houses which had 11ft of water through them were dry in 5 days.

[martin19842]

hi there,

the developer is picking up the cost of the repairations,and therefore the dec cost is minimal.

we provide a 24/7 service for this client, and these larger jobs are rare, i strongly believe that we have this under control, whilst hints and tips are always welcomed.

it is interesting though, that these water out type systems require a level ground to operate from, and ironically enough this premises, is surrounded by uneven ground.

anyway have a great weekend everybody.

regards

martin

[DP]

HI martin
It seems the server in the states is still down so I have amended my email address temporarily on my profile.