 | Home > Off Topic > Anyone fitted a PIV system in a house |
 
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| pjw4233 Member Since: 30 Nov 2009 Location: Lake District & Cheshire Posts: 273   
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De humidifiers are only any good if you keep all the windows and doors closed.
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18th Nov 2015 12:22am |
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| stew 46 Member Since: 26 Jan 2012 Location: Wadebridge ,cornwall . Posts: 561  
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And will work 30% quicker with a fan working at the same time to move the air
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18th Nov 2015 12:39am |
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| Ads90 Member Since: 16 Jun 2008 Location: Cots-on-the-Wolds Posts: 812 
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Ive not installed a PIV myself, but the issues of damp in old properties is something Im unfortunately very familiar with, both in my own house and in many that I help to look after as part of my work.
It seems to me that the principles of the PIV are perfectly reasonable, although these particular units seem a little costly for what they are, and they would have to rely on a natural, even distribution of air around the whole house. So I too would be interested in hearing from a member who has installed one, as an alternative to reading Amazon reviews, which Im sometimes a little suspicious of My thoughts on period properties is that although 100+ years ago they would have had considerably more natural ventilation from open fireplaces and poorly fitting doors & windows etc., many were probably always damp to start with, due to lack of tech such as dpcs, dpms, roofing felt etc. and any form of insulation to combat cold surfaces and so condensation. We now tend to reduce the air flow by fitting stoves in fireplaces, draught excluders around openings, and blocking-up air vents, at the same time as increasing the humidity by using power-showers several times a day! Anyway, without knowing your particular circumstances, or what you have already tried this is my usual check-list when addressing damp in old cottages: 1. Make sure there are no rain water ingress issues such as leaking/blocked gutters & downpipes, missing roof tiles, pointing, flashing, etc. that are exasperating the issues. 2. Similarly, if you have solid stone walls like many do here in the Cotswolds, and the external ground levels are high, look at either lowering the ground level where practical, or installing French drains and back-fill with gravel to help reduce the external water pressure. Note I have had some success with newton-lath type of internal lining where rising damp has been persistent and all else has failed, although I dont like using it in principle, as it can trap water behind causing it to rise still further. 3. Ensure the usual extraction in bathrooms & kitchen is as good as it can be - I have seen considerable improvements from just upgrading existing extract fans in bathrooms etc. to types with humidistat controls which can run on constant trickle settings where required. 4. Make sure there is enough permanent natural ventilation around the house tricky in period properties I know, when windows may not have trickle vents, but ideally keep windows cranked a little where security isnt a concern. 5. Try and keep the house at a constant (warmish) temperature throughout the colder months. I know this can seem extravagant if you are out of the house for periods of time, but in old houses with high thermal mass, the fabric takes time to heat up and cool down, often getting out of sync with the occupancy. Running the heating on tick-over can sometimes be more efficient than turning it up high when you get in then switching it off at night or when away. Generally, the warmer the fabric, the less likely to have condensation. 6. If you still have problems, and/or cannot get enough natural ventilation without causing uncomfortable cold draughts - then I would consider some form of whole (or part) house MVHR. The PIV is a very basic form of this, and may be worth a punt, but I would rather have in-built heat recovery to raise the efficiency and comfort of the system. The main problem is still going to be ensuring even distribution of the air around the house without having unsightly ductwork all over. But you could start with a smaller system, just targeting problem areas, and increase if necessary. Another key advantage of MVHR over PIV is that you don't have to rely on natural ventilation - you can close the windows! As youve probably already identified, warmth & ventilation are key to reducing humidity and condensation, without relying on dehumidifiers. And of course it helps if the water isnt seeping through from the outside! Anyway, thats enough of a ramble hope its of some use! |
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18th Nov 2015 2:39am |
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| stew 46 Member Since: 26 Jan 2012 Location: Wadebridge ,cornwall . Posts: 561
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In my experience as a builder in north Cornwall for the last 30 odd years there's a few things that will help , some mentioned above by Ads90 . 90% of damp problems is moisture retention , and modern heating and not having a thermal break , some times the only application we will use is the delta system , ( delta membrane ) it's a semi rigid membrane that formers a small cavity on the inner leaf of your house so forming a thermal break
I would NOT recommend a tanking system .
Stew. |
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18th Nov 2015 6:53am |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610 
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I used to have issues with a property with damp where the gutters were not deep enough for the pitch roof area and volume of water when it rained hard. Subsequently the gutters used to overflow causing dampness in kitchen and bedroom areas.
Have you considered a 'heat recovery system' or individual heat recovery fans? Basically they have a humidity sensor and will extract damp air when sensed and replace with dry air at the same room temperature. This setup for me worked very well indeed, so much so I have used their single fan unit as an alternative to a basic bathroom extractor in every property bathroom since. http://www.kiltox.co.uk/products/ventilati...lation.htm If you go through life with your head in the sand....all people will see is an ar5e!! Treat every day as if it is your last....one day you will be right!! |
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18th Nov 2015 11:25am |
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| Lambley Member Since: 20 Apr 2013 Location: Mid Devon Posts: 1435 
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Thanks for the replies, much appreciated. Ads90 - that must have taken ages to type up, very informative thank you.
Mal - I'll look into the heat recovery systems too, they sound like an upmarket version of the PIV systems I've been looking at but work in a slightly different way. Our property is probably 200+ years old, most of it is cob that's been rendered over, and then there's an extension that I'm sure is brick and breeze block, also rendered. Part of the problem is the heating system - it's crap so we don't use it, it's an old electric boiler that takes an eternity to warm up, and the radiators never seem to get up to a decent temp. I'm waiting until the spring to put a log/multi-fuel burner in which should help warm the place up and create a draw and move air around. I've got lots of wood and don't mind burning it, electricity bills kill me. The walls vary in thickness but nearly 3 feet thick in places and fitting an extractor isn't easy. Also, the surveyor pointed out that the render is not lime based, they have used cement, apparently on older houses this is not good practice and lime render should have been used. I'm no builder but I'm handy and have plenty of time on my hands, in the spring I've got a list of jobs to do - French drains and ditches around the property (we are on private drainage and septic tank but the rainwater can go into the stream near the house) Remove a 2nd chimney that's defunct and a new roof over the extension (it's flat fibreglass at the moment) Remove the render and start again with lime render or similar I'm hoping that this will cure at least 75% of the problem, there was an old lady living here before us and I don't think she'd had much done for the last 35 years. If one of these systems helps us out and cures some of the condensation then I'd be more than happy. |
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18th Nov 2015 12:48pm |
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| Cupboard Member Since: 21 Mar 2014 Location: Suffolk Posts: 2971 
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the advantage of the heat recovery units is they don't throw the heat away, which positive pressure ventilation does do.
If you're thinking about changing your heating system, we put wood pellet boilers in a couple of our houses that had woeful heating systems. The running costs are much less than oil and electricity, installation costs are higher but that's offset by ongoing Renewable Heat Incentive payments. Overall, it's good for the tenants because their bills are lower, its good for us because we have happy tenants, we're doing a bit more to help the environment and we got a subsidised heating system. |
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18th Nov 2015 1:08pm |
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| Petronius4 Member Since: 07 Oct 2015 Location: Somerset Posts: 94 
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You are quite right about the Lime render. Houses of this era used to act like a sponge/syphon - the moisture in the walls was sucked up through the lime render to the roof cavity by natural air flow. Check you don't have too much loft insulation packed around the meeting of roof/walls and although its going to be expensive consider removing the cement and returning to lime render. Only paint the lime render with a compatible paint as stuff such as weather shield prevent the wall from breathing and over time small cracks in this type of paint allow water ingress but not enough 'breathing' to dry out, = damp.
------------------------------- 👲🏻 1986 ex-Military 90 NAD 2.5 Soft Top. Sold 🇬🇧 2015 Defender 90 - Ripon Landrover Heritage 006 |
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18th Nov 2015 3:39pm |
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| Petronius4 Member Since: 07 Oct 2015 Location: Somerset Posts: 94
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As an after thought: a house of this age probably doesn't have a damp course so you will be sucking up moisture from the ground and because you have cement render and no cavity in the wall the only outlet for the moisture will be through the internal wall. Replacing with lime render and taking the house back to as much of its original build material as possible will fix this - the ancients knew a thing or two about house building (prob used a Series I to move the hay around...) -------------------------------
👲🏻 1986 ex-Military 90 NAD 2.5 Soft Top. Sold 🇬🇧 2015 Defender 90 - Ripon Landrover Heritage 006 |
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18th Nov 2015 3:48pm |
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| Lambley Member Since: 20 Apr 2013 Location: Mid Devon Posts: 1435
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Well, I spoke to a few retailers and fitted a Nuaire system a few days ago and so far it's doing a perfect job. Very easy to install, almost silent running and there's been a massive drop in condensation. I'm sure other things that will get done over the coming years will also help (re-render, French drain etc) but so far I'm very impressed, it's early days but I'm convinced that lower condensation will lead to a dryer house, less black mould around window frames etc.
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28th Nov 2015 5:11am |
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| Fish Member Since: 21 Jan 2014 Location: United Kingdom Posts: 58 
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We are developers and I use the Drimaster 2000 and have one in my house... brilliant piece of kit and does exactly what it says on the tin. I've now fitted over probably 400-500 and no complaints from anyone except when they have switched them off!
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23rd Jan 2016 7:25pm |
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| Lambley Member Since: 20 Apr 2013 Location: Mid Devon Posts: 1435
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I fitted a Nuaire Drimaster Heat, absolutely brilliant, best mod I've done in the house so far.
Very good so far, it's made a massive difference to the condensation problem, no more wet windows in the morning, less damp, overall I'm very impressed  |
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23rd Jan 2016 10:20pm |
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