Condensation - Help!

[richo106]

Good Afternoon

 

I am currently at the stage where 95% is plastered and 70% plastered and I have finally got the ASHP up and running and got some heat in the house Saturday morning

 

When I arrived at the house Sunday there was quite a lot of internal condensation on all the windows, enough to run down onto the window boards in most cases.

 

What is causing this and is there anything I can do to help with this at all!? and is this normal...got me quite worried. Is it just things that are damp drying out? 

 

I have MVHR installed (but not on/commissioned yet) so have tried to make the house as air tight as possible, still have a couple of holes to address

 

Any advice at all on this

 

Thanks in advance

[Conor]

Your house is full of 100s of litres of water. Open the windows. It'll take weeks to dry. All heating is doing is lifting the water from warm parts and depositing it on cold parts.

Edited November 27, 2023 by Conor

[richo106]

OK thanks @Conor

 

When you say open the windows, is it ok to leave on the latch so its only open slightly?

 

Many Thanks

[Conor]

I found the roof lights upstairs had to be open a good couple of inches, or else the reveals would be soaking the next morning. Rest of mine are tilt and turn so just left them tilted in, so about a 80mm gap. Experiment and see, but I'd leave the top floor windows / roof lights on more than just the trickle latch. Also, don't raise the temp of the house too quickly. Start at 12c and bring it up a degree or less per day. Two weeks to get to 20c.

 

We soon sealed up and used dehumidifiers tho, more efficient and effective. Bought five £120 ones from Screwfix and sold them all on a year later for £80- £100 each.

Edited November 27, 2023 by Conor

[Kelvin]

1 hour ago, richo106 said:

OK thanks @Conor

 

When you say open the windows, is it ok to leave on the latch so its only open slightly?

 

Many Thanks

Open them  when you’re there especially any upstairs windows or rooflights. I have a couple of oiled filled rads doing the heating and we are about 50% plastered and we have condensation running down corners of the windows and handles. You can put a dehumidifier in too. 

[richo106]

I have bought 2 dehumidifiers to stick upstairs. As downstairs seems ok, I have no loft insulation though at the minute which doesn’t help either as it’s cold upstairs especially this week!

 

would turning my MVHR on help at all? 

[Redbeard]

Why are you paying for heat when you effectively have a hole in the top of the house? Would it not wait till you have the insulation in, then a given temp rise costs you much less...

 

No idea why font is pale and tiny.

Edited December 1, 2023 by Redbeard
Font moan

[richo106]

3 minutes ago, Redbeard said:

Why are you paying for heat when you effectively have a hole in the top of the house? Would it not wait till you have the insulation in, then a given temp rise costs you much less...

 

No idea why font is pale and tiny.

Everything was starting to feel a little damp that’s all. I thought it might benefit with a bit of heat in the house 

[richo106]

Next weekend I’ll be installing the loft insulation 

[MikeGrahamT21]

Plastering at this time of year is problematic for condensation, I was in the same position last year around this time but had MVHR running, along with a dehumidifier, the amount of water which was removed was bonkers, you’ll get there eventually but it’ll take time, from memory I think I was battling it for around 2 weeks with normal heating on, around 15m2 of plastering but I used bonding coat and plaster rather than dry lining which increased water content

[richo106]

I haven't powered up my MHVR up at all yet but I am open to anything that will help with this issue etc

 

I haven't got any control vents on the outlets yet either, can I just power up the MVHR and let it run? Would it be best to remove the filters too?

 

Any advice on this very much appreciated

 

Many Thanks

[Mr Punter]

I don't think your MVHR will do much for the condensation.  Dehumidifiers are the way.  Plumb them into a waste if you can so you don't need to mess around emptying them.

 

If you are around during the day, switch off the dehumidifiers and open doors and windows.

 

Obviously a cold and pissing wet winter means it will take a while to dry.

[Russdl]

4 hours ago, richo106 said:

can I just power up the MVHR and let it run?

I would resist the urge to do that until you are pretty much complete and have stopped creating dust etc. Removing the filters would keep them clean but everything else will get contaminated. 

[MJNewton]

If you do run the MVHR (I would - find it great for drying washing so the dehumidfying effect is definitely there) keep the filters in place. They protect the heat exchanger from becoming fouled up. 

[richo106]

Another condensation issue, this time in the loft.

 

I have been in my loft tonight and there is condensation on the underside of my black roof lining.

 

There is condensation between my airtight layer and plasterboard 

 

Also there must lots of condensation in my MVHR ducts in the loft (not insulated yet) I knocked one as moving around and a lot of water came out the room vent!

 

I think the majority of my condensation issues have come about as I had the heating on low which meant warm air hit the cold air in the loft etc

 

will this dry out naturally? Could this cause me any issues with anything?

 

Anything I can do to help?

 

Sorry for all the questions but it’s just another problem for me at the minute

 

Thanks again 

 

 

[MikeGrahamT21]

What type airtight membrane did you use? Ideally should be an airtight vapour control membrane (AVCL), and if sealed correctly moisture shouldn’t have been able to reach the loft unless you have masonry elements which travel up there.

 

see what others say but for me you really need to hit it hard and try getting as much moisture out as possible, quickly, you run the risk of getting mould growth as it is, which would lead to ripping plasterboards out and replacing. Hiring an industrial dehumidifier (or 2 depending how big an area) wouldn’t be a bad move

[Ferdinand]

Dehumidifier Tips and Recommendations.

 

1 - Remember DHs are specced at about 30C, so you need to heat it up as well. Good job we are all building well-insulated airtight houses.

 

2 - Buying, using and selling is a good plan, as so often. Either new or ebay.

 

I have about 5 DHs, as I am an LL and need industrial ones to dry out houses being restored or if Ts ever flood it (only once).

 

My biggest one weighs 60kg and does 60l/day, but my favourite is a Broughton CR 40, which is portable and compact, and in my experience shifts a lot of water:

https://www.broughtoneap.co.uk/products/dehumidifiers/cr40/

 

(Still available secondhand or refurbished for about £200-400.)

 

3 - Also, what about using one of the Reversible Heat/Cool/Dehumidifier incorporating a heat pump that we were all talking about?

 

a - Plug it in as a heater to boost the temperature for a half day using the heat pump heater - with the duct through the window in a baffle you create. Mine puts out 3.2kw for 1.3kw input - ish.

b - Close window, and switch to dehumidifier mode.

 

I have this one, Airflex 15 - there are others, which is domestic enough to keep to dry washing. £370 new. £300 refurbished.

https://www.appliancesdirect.co.uk/p/airflex15/electriq-airflex15

 

You will also need an insulated ventilation duct.

 

[richo106]

I used this

 

https://www.insulationsuperstore.co.uk/product/powerlon-vcl-170-air-and-vapour-control-layer-2m-x-50m.html

 

Would you recommend putting the de humidifiers in the loft?

 

To be honest airtightness was an afternoon during the build but I have tired my hardest to keep it airtight. I currently have some holes in it that I need to across anyway so guessing this wouldn’t of helped 

 

You have made me panic even more now 😂🙈

[richo106]

3 minutes ago, Ferdinand said:

Dehumidifier Tips and Recommendations.

 

1 - Remember DHs are specced at about 30C, so you need to heat it up as well. Good job we are all building well-insulated airtight houses.

 

2 - Buying, using and selling is a good plan, as so often. Either new or ebay.

 

I have about 5 DHs, as I am an LL and need industrial ones to dry out houses being restored or if Ts ever flood it (only once).

 

My biggest one weighs 60kg and does 60l/day, but my favourite is a Broughton CR 40, which is portable and compact, and in my experience shifts a lot of water:

https://www.broughtoneap.co.uk/products/dehumidifiers/cr40/

 

(Still available secondhand or refurbished for about £200-400.)

 

3 - Also, what about using one of the Reversible Heat/Cool/Dehumidifier incorporating a heat pump that we were all talking about?

 

a - Plug it in as a heater to boost the temperature for a half day using the heat pump heater - with the duct through the window in a baffle you create.

b - Close window, and switch to dehumidifier mode.

 

I have this one, Airflex 15 - there are others, which is domestic enough to keep to dry washing. £370 new. £300 refurbished.

https://www.appliancesdirect.co.uk/p/airflex15/electriq-airflex15

 

You will also need an insulated ventilation duct.

 

Actually I have one of these, which is in the garage and didn’t think to use!

https://www.delonghi.com/en-gb/pacn90ecosilent-pinguino-portable-air-conditioner/p/PACN90ECOSILENT?sv1=affiliate&sv_campaign_id=369493&awc=25781_1702071072_d0af15ef9f43b7fea78a343ec35f57fb&utm_source=aw&utm_medium=affiliation_uk&utm_campaign=SHOPIA

 

if it was on de humidifier mode would I still have to vent it outside? 

 

I don’t think there is much of a water container though 

 

 

[Ferdinand]

2 minutes ago, richo106 said:

I used this

 

https://www.insulationsuperstore.co.uk/product/powerlon-vcl-170-air-and-vapour-control-layer-2m-x-50m.html

 

Would you recommend putting the de humidifiers in the loft?

 

To be honest airtightness was an afternoon during the build but I have tired my hardest to keep it airtight. I currently have some holes in it that I need to across anyway so guessing this wouldn’t of helped 

 

You have made me panic even more now 😂🙈

 

There's no harm imo, as long as it has something firm to stand on, perhaps as a quick hit. If there is no source of moisture up there, then drying it out and closing the hatch should keep it that way.

 

But if the loft is not draughty and the hatch is open reducing the humidity in the house should suck it out quickly.

 

I would recommend a couple of the inexpensive £10 min/max thermometer-humidity meters to let you monitor. Like this one:

https://www.amazon.co.uk/ThermoPro-TP50-Digital-Thermometer-Temperature/

 

F

[Ferdinand]

16 minutes ago, richo106 said:

Actually I have one of these, which is in the garage and didn’t think to use!

https://www.delonghi.com/en-gb/pacn90ecosilent-pinguino-portable-air-conditioner/p/PACN90ECOSILENT?sv1=affiliate&sv_campaign_id=369493&awc=25781_1702071072_d0af15ef9f43b7fea78a343ec35f57fb&utm_source=aw&utm_medium=affiliation_uk&utm_campaign=SHOPIA

 

if it was on de humidifier mode would I still have to vent it outside? 

 

I don’t think there is much of a water container though 

 

 

 

Need to think about this.

 

Normal dehumidifier you don't need the hose, but this looks unusual.

 

If in doubt, follow the manual !

[richo106]

Thank you @Ferdinand I already have 2 small de-humidifiers running and they pull about 5L day between them as I haven’t had chance to plumb them in yet. So trip out each day when water is full

 

I will certainly put the other larger one on tomorrow after the plasterers have finished for the day.

 

I can heat up the house using my ASHP and under floor heating, I have turned the heating off as I thought this was causing my condensation issues as have no loft insulation 

 

Daft question…do I need to wait until the moisture has dried out between the vcl and plasterboard before laying insulation over the top? 
 

thanks again

Edited December 8, 2023 by richo106

[richo106]

This is taken from the manual

 

DEHUMIDIFYING MODE

Ideal for reducing the humidity in a room (spring or autumn, damp rooms, rainy spells, etc). When the dehumidifying mode is selected, the light (P) comes on.

In this mode, with temperatures higher than 25°C it is possible to adjust the ventilation speed.

If the temperature is less than 25°C the ventilation speed will be automatically adjusted by the appliance and the ventilation light "MED" (L) will turn on.

Note: remember to fit the air exhaust hose as described in the chapter "Preparing for use".
 

 

[richo106]

Looks like it recommends installing the hose and venting outside. 
 

This would leave me with a window open though 

[MikeGrahamT21]

11 hours ago, richo106 said:

Thank you @Ferdinand I already have 2 small de-humidifiers running and they pull about 5L day between them as I haven’t had chance to plumb them in yet. So trip out each day when water is full

 

I will certainly put the other larger one on tomorrow after the plasterers have finished for the day.

 

I can heat up the house using my ASHP and under floor heating, I have turned the heating off as I thought this was causing my condensation issues as have no loft insulation 

 

Daft question…do I need to wait until the moisture has dried out between the vcl and plasterboard before laying insulation over the top? 
 

thanks again

If it’s trapped in between the PB and VCL insulate as it’ll raise the temperature and allow the moisture to evaporate again, remember moisture will go for the coldest spot.

 

have you determined the cause of the moisture making it into the loft itself?

 

apologies for the panic, I think most of us have been there! At least as it is you have opportunity to rectify the situation, just needs fast action.

 

drawing 5l per day is something but won’t get on top of it, there will be hundreds of litres to come out.