PIV

jimjam83

We recently had a damp specialist tell us that we need to rip our walls down, install a membrane, replaster, etc. He terrified us! We only have a small issue with what seems to be condensation, it appears around windows with no radiators beneath them. We have clammy walls but no mould. I’ve heard amazing things about PIV systems. I’ve seen a few old threads on here but does anyone have any recent experience or feedback they can share? Can they be installed by an amateur DIY-er?!

MovingForwards

What's on the otherside of the wall / windows?

tacpot12

A combination of heating and ventilation can usually solve most condensation problems. Sometime it may be necessary to insulate the walls, either with an insulated lining paper or insulated plasterboard. I would always try improving the heat, ventilation and insulated lining paper before moving to more expensive solutions.

Installing a membrane would usually only be required if the walls had bare earth behind them, such as if the house was built into a hillside. PIV generally works well, but increases your heating costs slightly. 

greyteam1959

I have had a Nuaire Drimaster in my house for about 20 years.
Brilliant piece of equipment, stopped all mould & condensation in my 1910 built house.
Very easy to DIY fit.
It does however blow in cooler air from our loft space that has no underfelt.
I think the units are around £250 now but I could be wrong.

tacpot12

The Drimaster units can have thermostatic heaters fitted so that if the air is cold outside or in the loft, it is warmed before being pumped into the house. Although this drives up the electricity bill, in theory, it should reduce the usage of other forms of energy used to heat the house, but in practice a PIV does waste a bit of heat. The alternative is a mechanical heat recovery venitlation  (MHRV) system which is basically a PIV where the air is forced out of one central vent (rather than many small vents around the building) and a heat exchanger that recovers the heat from the air stream leaving the building to warm the air coming in. The heat exchanger is never 100% efficient, so some supplementary heating is still needed, but it is much more efficient that PIV. The cost of MHRV systems is so much greater than PIV that you normally only find them on new builds because they need so many years to recover their capital cost. 

FreeBear

jimjam83 said: We recently had a damp specialist tell us that we need to rip our walls down, install a membrane, replaster, etc.

You did not have a "damp specialist", you got a snake oil salesman scaring the living daylights out of you in the hope that you'd cough up £xxxx for his "cures". If this is the 1876 terrace you were buying back in October, don't do anything until the summer. Get some heat in to the walls and some fresh air once it is warmer outside. Get yourself a couple of cheap hygrometers and monitor the humidity levels (take regular readings). 50-60% at around 20°C would be reasonable rising to 60-65% in the kitchen or bathroom.

Solid brick walls really benefit from having lime plaster applied internally, and left bare externally (or rendered in lime). Painting the walls with a modern plastic paint compromises the ability for the plaster to "breath", and gypsum plaster (the pink stuff) turns to mush when exposed to long periods of damp. Having a mix of painted walls, gypsum plaster, and traditional lime plaster will throw off any readings from a pointy damp meter - Not that one can be used to give a definitive reading on anything other than untreated wood... Good for scaring the pants off an unsuspecting sucker customer though.

Apodemus

FreeBear has, as usual, put it better than I can.  It's typical "Damp Specialist" behaviour.  Just forget everything the "specialist" said, chalk it up to experience, relax and move on.  Your house has been there a while and will be there for many more years - Enjoy!

RelievedSheff

Agree with the above. Ignore the "damp specialist" and heat the house properly and ventilate it properly.

Open the windows once a day to let some fresh air around the property and the damp stale air out. Keep the house heated to allow it to warm through properly. Use extractor fans in the bathroom and kitchen to let the moisture out after bathing and cooking and keep doors closed to these rooms to keep the moisture from spreading to the rest of the house.

If you keep the house well heated and well ventilated chances are your "damp problems" will disappear given time for the property to dry out. You can use a dehumidifier to speed up the drying out process if you think it necessary but it doesn't sound as though you have massive damp issues.

jimjam83

FreeBear said:

jimjam83 said: We recently had a damp specialist tell us that we need to rip our walls down, install a membrane, replaster, etc.

You did not have a "damp specialist", you got a snake oil salesman scaring the living daylights out of you in the hope that you'd cough up £xxxx for his "cures". If this is the 1876 terrace you were buying back in October, don't do anything until the summer. Get some heat in to the walls and some fresh air once it is warmer outside. Get yourself a couple of cheap hygrometers and monitor the humidity levels (take regular readings). 50-60% at around 20°C would be reasonable rising to 60-65% in the kitchen or bathroom.

Solid brick walls really benefit from having lime plaster applied internally, and left bare externally (or rendered in lime). Painting the walls with a modern plastic paint compromises the ability for the plaster to "breath", and gypsum plaster (the pink stuff) turns to mush when exposed to long periods of damp. Having a mix of painted walls, gypsum plaster, and traditional lime plaster will throw off any readings from a pointy damp meter - Not that one can be used to give a definitive reading on anything other than untreated wood... Good for scaring the pants off an unsuspecting sucker customer though.

Ok - I am taking this advice and running with it. We had another snake here today trying to flog a Dutch system to us. He spent 35 mins discussing his anti-vax policy and the rest of the time measuring outside. Weve now had 3 different “professionals” tell us 3 different things. So we’re going to do nothing. I’m gonna leave the dehumidifier on at 50% as it shuts down and restarts itself. 

I’m so glad we didn’t go with the first guy. 

Thank you!!

FreeBear

jimjam83 said: We had another snake here today trying to flog a Dutch system to us. He spent 35 mins discussing his anti-vax policy and the rest of the time measuring outside.

By the sounds of it, you are able to spot the charlatans and cons..

On the subject of vaccines & conspiracy theories... Why go to the expense of creating a global pandemic to sell vaccines in an attempt to inject the entire population with GPS trackers... Get them hooked on social media and you can track their movements via their phones. Added bonus, they pay you to monitor their every move and you get to flog the latest & greatest phone every two years or so.

rob7475

FreeBear said:

jimjam83 said: We had another snake here today trying to flog a Dutch system to us. He spent 35 mins discussing his anti-vax policy and the rest of the time measuring outside.

By the sounds of it, you are able to spot the charlatans and cons..

On the subject of vaccines & conspiracy theories... Why go to the expense of creating a global pandemic to sell vaccines in an attempt to inject the entire population with GPS trackers... Get them hooked on social media and you can track their movements via their phones. Added bonus, they pay you to monitor their every move and you get to flog the latest & greatest phone every two years or so.

LOL - totally agree. The foil had brigade who reckon we're being injected with trackers will quite happily be walking around with mobile phones. Whether you like it or not, you're being tracked already