Condensation Solution?

by Readers Question

8:14 AM, 12th June 2015
About 3 years ago

Condensation Solution?

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Condensation Solution?

I have a flat with a concrete roof. It is top floor and the roof is flat. Below that by some 2-3 feet is a suspended ceiling with a grid/frame of tiles. Condensation Solution

My problem is condensation. There has been a steady drip of water onto the tiles from the cold roof. This also results in damp on the walls within the living space below.

I have been recommended a PIV system by Envirovent, who I am probably going to get in to do a survey.

First, I wondered what people’s thoughts might be? There is no leak – I have had a flat roof specialist look into it, and I’ve been up top myself. He tells me it is all condensation.

Would a PIV system cure this problem? How much should I expect to pay (if you know about them at all).

Thank you in advance.

Ian



Comments

Mark Alexander

8:18 AM, 12th June 2015
About 3 years ago

Hello Ian

I have used positive input systems from both Envirovent and Nuaire and had superb results.

You get a 10% discount discount off Envirovent if you are an NLA member and as the saving is greater than membership that's a bit of a no brainer. Nuaire is a lot cheaper but doesn't come with the same level of guarantees.

If you search this site for the phrase Envirovent or Condensation you will find quite a lot of discussion threads about this subject.
.

Paul Franklin

10:09 AM, 12th June 2015
About 3 years ago

Condensations problems are usually due to inadequate heating, insulation and/or ventilation - or a combination of all 3. PIV will sort the ventilation issue but as that concrete roof will be so cold and the water is condensing on it I wonder if there is any insulation that can be put between it and the suspended ceiling?

Also, is the heating system in the property adequate/efficient? And are the tenants using the heating? Cold air holds less moisture and cold spots and walls/ceilings will lead to condensation and mould.

Jerry Jones

10:30 AM, 12th June 2015
About 3 years ago

I wonder if a first step might be to insulate the roof structure to prevent the cold surface in the first place?

Joe Bloggs

11:54 AM, 12th June 2015
About 3 years ago

Reply to the comment left by "Paul Franklin" at "12/06/2015 - 10:09":

Paul - INSULATING THE VOID WILL BE POINTLESS unless a vapour barrier is incorporated.

Ian - is there black mould on the underside of the roof and on windows etc/ if the answer is no then its not condensation. does the dripping only occur during/ after rain? if the answer is no then its not condensation. is the dripping just in the lounge? if the answer is YES then its not condensation.

mr buddah

17:43 PM, 12th June 2015
About 3 years ago

seems to be similar to my place. At the time I just could not believe this was condensation, it just had to have been a leak. Anyway, I took the roofer's advice and fitted another layer of plasterboard on the ceiling and against the inside of outside facing walls and, hey presto, the problem disappeared. Recommend you use plasterboard with the tin foil on the back as this provides a vapour barrier. The room even feels warmer although tenants never heat it

Stephen Linley-Shaw

20:50 PM, 12th June 2015
About 3 years ago

Insulation will not change the problem of high humidity - it may even stop water vapour escaping.
Heating the air more will allow the humidity to rise.....this adds to the problem!

You are suffering from high humidity. You can either reduce the water vapour you create (virtually impossible) or expel the damp air.

Positive input ventilation will work . ..... as a damp expert I recommend you install a Nuaire Flatmaster - cheapest solution.

i have been in the industry for 30 years, at dryhomes . net ,and can assure you this is the best advice

Warmest wishes

Stephen Shaw

Joe Bloggs

1:57 AM, 13th June 2015
About 3 years ago

Reply to the comment left by "Stephen Linley-Shaw" at "12/06/2015 - 20:50":

'Heating the air more will allow the humidity to rise…..this adds to the problem!'

VERY SURPRISED THAT SOMEONE CLAIMING TO BE AN EXPERT WOULD MAKE STATE SUCH A MISLEADING CONTENTION.

HUMIDITY IS NOT THE ONLY FACTOR THAT CAUSES CONDENSATION. THE OTHER VITAL FACTORS ARE SURFACE TEMPERATURE (WHICH IS A FUNCTION OF HEATING AND INSULATION) AND VENTILATION. IN FACT THE OPPOSITE OF WHAT YOU STATE IS TRUE, I.E. SPACE HEATING REDUCES CONDENSATION; IT DOES NOT 'ADD TO THE PROBLEM'.

HEATING RAISES DEW POINT WHICH MEANS THE AIR CAN HOLD MORE WATER VAPOUR. HOWEVER CONDENSATE WILL ONLY FORM ON COLD SURFACES IF THEY ARE BELOW DEW POINT, I.E. IF THERE IS INADEQUATE HEATING! FURTHERMORE, VENTILATION IS MORE EFFECTIVE IN EXPELLING WATER LAIDEN AIR THAN ACTUAL CONDENSATE.

INSULATION WILL NOT PREVENT WATER VAPOUR ESCAPING UNLESS IT IS VAPOUR TIGHT, WHICH MOST INSULATING MATERIALS ARE NOT.

Stephen Linley-Shaw

10:23 AM, 13th June 2015
About 3 years ago

Reply to the comment left by "Joe Bloggs" at "13/06/2015 - 01:57":

Hello Joe

Sorry to contradict your last comment but there are 2 myths about condensation..........

1. increasing the heating will solve the problem.
This will only work IF ventilation is also improved AND the raised heat level is maintained. Heating is a very expensive way of solving a ventilation problem.......most tenants suffering the problem do not have money to heat the house 24/7- they switch it off and night and the higher humidity causes WORSE CONDENSATION at night.

2. Improving insulation will solve condensation.
Wrong. Condensation will still occur if the humidity problem has not been tackled. you can insulate all the walls, floor and ceilings - a very expensive "exercise" - but the windows will then start streaming even worse than before...WHY ? Because the windows have become comparatively cold and water condenses on the coolest surfaces first.

Heating is a permanent expense and solves nothing! Insulation is essential to improve the energy saving and should be encouraged for that reason - not to combat condensation.

I have been in the condensation control business at Dryhomes and Dampco for over 30 years and the cheapest, fastest and most effective way of solving condensation is PIV. Positive Input Ventilation.

We install many Nuaire Drimasters and other PIV products each week, in South Devon, and all are effective.

Mark Alexander

11:01 AM, 13th June 2015
About 3 years ago

Reply to the comment left by "Stephen Linley-Shaw" at "13/06/2015 - 10:23":

This will be an interesting debate, qualified surveyor vs experienced PIV fitter 🙂
.

Stephen Linley-Shaw

11:32 AM, 13th June 2015
About 3 years ago

Reply to the comment left by "Mark Alexander" at "13/06/2015 - 11:01":

Good morning Mark

Which is which?
I am an experienced fitter of PIV units for 20 years AND a qualified Damp and Timber Treatment Surveyor with the PCA + qualified Waterproofing Surveyor.
At Dampco / Dryhomes we know all about damp.....and can solve most problems.

I do not know Joe Bloggs but thank him for giving me an opportunity to balance the CONDENSATION argument in favour of real science over 'common sense', myth and here-say.
Best wishes
Steve

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