mvhr and plastering

[j_s]

I've finally sorted out my loft insulation and switched on my mvhr today, still to balance etc but it's been a long journey so will look at that another day. We have the plasterer in to do 2 rooms a week tomorrow, one a bedroom, the other the dining room. Can/should I leave the mvhr on during and after the plastering. I have read but not found the forum post (old site, gbf or here) that it will help to dry it out quicker and help with the excessive moisture especially now it's winter. 

 

Thanks all

[ProDave]

Turn it off while he is plastering as it might be dusty while he is mixing, but turn it back on when done.

[lizzie]

I would put some covers over the vents too so you stop the dust going in and getting sucked through the system when you switch on

[MikeGrahamT21]

Leave it a couple of days until the plaster is visibly dry, remember the slower the plaster dries the stronger it will be, and you want it to last a lifetime ideally, with the heating on at this time of year it won't take more than a couple of days. Also gives chance for plaster dust to settle, and you to clean it up, as its very fine, will clog the filters up well.

[j_s]

Hi Mike that was my worry but what I've read elsewhere is that as it's room temp anyway it won't cause the issues a dehumidifier or big heaters would. All it will serve is to push the excess moisture in the room to an extract point. I could just turn the mvhr to low mode after the plastering is done so it's as gentle as possible. 

 

I'll switch it off when it's being done and then add the protective covers and then give it a day or 2 max 

 

Thanks all

[MikeGrahamT21]

Sounds sensible if you want to get the MVHR turned back on ASAP, longer you can leave it the better though. Dehumidifiers and heaters lower relative humidity causing the plaster to give off its moisture too quickly, and in turn weakening it. MVHR will have the same effect, especially at this time of year.

 

Best thing to do is just leave a window slightly open in the rooms being plastered, this way you can guarantee a slow dry, and the air temperature will also be reduced.

[Ed Davies]

8 hours ago, j_s said:

All it will serve is to push the excess moisture in the room to an extract point.

Thereby reducing the humidity and therefore increasing the drying rate. Just like a dehumidifier.

[j_s]

2 hours ago, Ed Davies said:

Thereby reducing the humidity and therefore increasing the drying rate. Just like a dehumidifier.

 

Agree, but had hoped if the air rate was low enough it wouldn't cause issues with the plaster 

[ProDave]

We put the dehumidifier on the day after the plasterer finished. Until we did the windows were running with condensation and SWMBO was complaining the washing on the pulley was not drying, so we had to remove all that excess moisture from the house.  Too cold at this time of year to leave windows open, but that is what we did for the last lot of plastering done in the summer.  (we are living in the house so don't want it getting cold)

 

2 days later it was all bone dry and we were painting the plaster.  Not a crack to be seen anywhere.

[joe90]

Takes me back to when the plasterers finished and the liquid floor screed was put down this time last year (in a very wet Devon) windows were running with condensation despite a small dehumidifier running 24/7, so we hired two commercial units and ran them fir nearly two weeks as the only way to dry out the building. The MVHR was not run at all to avoid any problems.

[j_s]

Little update, mist coats went on 2 weeks ago. All dried nicely