Which way to self insulate a Wimpey No Fines House  

  RSS

DrJohn
(@drjohn)
Active Member Registered
Joined:6 years ago
Posts: 15
25/10/2018 10:21 pm  

Hi everyone, I’ve noticed quite a few posts lately about Wimpey no fines houses. Whilst I don’t know very much about these properties myself, I did come across a forum discussion on the internet which may be of use for some.

I’m posting a copy of the thread here even though it’s a few years old, just in case it’s useful to someone. I hope it’s ok to do so. I’ve edited the posters names though to hide their identity.

    • JohnDoe
    •  

    • Oct 23rd 2008 edited

     

    I have a Wimpey no fines (solid wall) mid terrace property which I purchased and it is in need of full re-decoration/renovation. As I will be redecorating I believe it might be a good idea to add some insulation to reduce the heat loss through the walls and it requires re-plastering also in many rooms.

    I am currently starting working in the lounge which has two external walls and each with a radiator on it. It is these two walls that really could do with being re-plastered, particularly the front wall which is in a pretty poor state with broken and uneven/not flat plaster. I would also like to insulate the two walls and despite researching I need some recommendations on what products to use to provide good insulation within a reasonable cost. I do not want insulation boards to be too thick as it would affect doors opening and space. About 35mm would be a maximum thickness.

    [EDIT] there is also an issue with the radiators and pipework. The radiator on the rear of the property has 15mm pipes inside a gap at the bottom of the wall, the gap to avoid damp rising in the plaster, and the pipes then go up the corner of the wall through the ceiling. The pipes inside the gap were intended to be covered by skirting board and at the moment the pipes are uninsulated so there will be heat around them and any insulating board that is applied. There is a similar situation for the radiator on the front wall but those are 10mm pipes ATM and I do want to replace them and redirect them to go up the corner of the room like the rear radiator as their current route needs to be changed. So there will be a similar situation for those pipes but I can insulate them providing there is sufficient room.

    What precautions would need to be taken to avoid condensation and damp when using internal insulation boards?

    I did find a link to a thermally insulating plaster which looked promising but before I could take note of the link or note down the name I had computer problems with required a system restore which lost the tabs which I had open containing the link. Despite searching I have not been able to find it again and I wondered if anyone on this forum knows about any thermally insulating plasters besides hemp lime plaster. The link I lost did look like it might have better thermal properties than hemp lime plaster.

    Finally what do I need to watch out for in relation to Building Regulations when insulating? How much of my property can be insulated before Building Regulations come into effect? Any links to relevant information would be appreciated.

    I hope that I can find some help here as I seem to be going round in circles and getting no where with this so far.


    • TT2
    •  

    • Oct 23rd 2008

     

    Is the party wall a cavity wall?

    Part L1b applies to anyone who re-plasters more than 25% of an element. For me you are doing the right thing so you are exempt — dont tell them!

    forget insulating plaster, use the best insulating ( and more expensive ) thermal board that you can find

    Ventilation will cure condensation problems but wait til a month after you have finished before deciding – a small in the loft heat recovery ventilation system would be good.


    • JohnDoe
    •  

    • Oct 23rd 2008 edited

     

    I don’t think the party wall has a cavity, it’s just a slightly thicker concrete (concrete as in large stones of around 1″ stuck together with a cement type substance with air spaces) than the external walls.

    The idea about the plaster is that if it needs doing, then every little bit helps. It would just be the cost involved as I would be doing it myself as the finish would not have to be perfect, just good enough for thermal board to be applied. The party wall itself has to be re-plastered as a leak next door in a council property damaged the plaster so the council has to cover the cost of repair of the plaster.


    • Walker
    •  

    • Oct 24th 2008

     

    Foam backed plasterboard (with the foam faced with foil) is going to give you much better levels of insulation than any wet plaster at that thickness. Nearly al come with a ‘feather edge’ which means rather than plastering over the top you (carefully) fill the join between boards until level with the rest of the board – then decorate on top. Depending on which product you go for the thicknesses run between 34-37 mm for the thinnest up as far as you like although beyond about a 50mm thickness of insulation it is hard to fit. does 35mm include your existing plaster or is that with it removed?

    Price should be under £30 (+VAT) per board (although like all things getting more expensive all the time)which come as 2.4 X 1.2 m sheets (feather edge on long side).

    Some links:

    http://www.insulateonline.com/
    http://www.celotex.co.uk/

    There are other manufacturers!

    I am a bit concerned about your ‘rising damp’ comment. That aside you would be well advised to surface mount all the pipework if only to make sure that your insulation forms a complete layer over the external wall. If it is not continuous you will be left with cold spots where condensation could form and cause problems.

    Keep asking questions before you jump!

    ‘Ventilation WILL cure condensation’ Tony – an uncharacteristically definite statement.


    • JJJ
    •  

    • Oct 24th 2008 edited

     

    Is it the no-fines type where there is an infill board between the front window and the underside of the first floor window? No fines was a type of construction introduced about 50 decades ago and is, more or less, what it says in concrete terms except that, with the no-fines came very low cement contents. This means that it has a very low strength compared to ordinary concrete.

    First rule of insulating most ‘no fines’: Do not insulate internally.


    • Walker
    •  

    • Oct 24th 2008

     

    JJJ

    I had no idea Wimpey were around at the turn of the 16 century – you learn something new every day.

    Jon, is the reason for no internal due to the extra dire consequences of condensation in weak concrete?


    • JJJ
    •  

    • Oct 24th 2008 edited

     

    Hi Walker

    Sorry about that: 50 years. The no-fines typical designs have their floor plates connected through to the external walls (usually in one direction with the other tied in flipping from front to back) and can have some of their internal walls (particularly in and around the stairwell) framed off these members: If you put internal insulation in then you transfer the condensation point to the bearing locations for the first floor and roof plate.

    Would keep you warm for a few years but won’t be much consolation when the perimeter support for the first floor and roof starts to rot!

    There may be exceptions: Depends which type IcanDoit has. And particularly, is it an ‘end of terrace’?

    JJJ


    • Walker
    •  

    • Oct 24th 2008

     

    No need to apologise at all, I’m a more than competent typo generator – it was just a relatively funny one. I don’t like smileys much but should have used one here I just like the idea of a 16th century Wimpey home.

    Thanks for the explanation. Similar to my 30’s house where the floor joists run into the walls and there are wooden lintels/ odd bits of wood in the walls.


    • JJJ
    •  

    • Oct 24th 2008

     

    Yes, though your 30’s house may have a cavity so would be less prone. No fines seem to me to be an ideal candidate for overcladding particularly given the flat construction and the relatively large overhang at the eaves on the typical ones (but that probably depends on location and era).


    • Walker
    •  

    • Oct 24th 2008

     

    We have a cavity downstairs up to just below first floor level but it is only about 40mm wide. All the wood is upstairs.


    • Walker
    •  

    • Oct 24th 2008

     

    JohnDoe

    If it is any consolation we though of just going for foam backed plasterboard in our house too but came to the conclusion after joining the motley crew here, reading the GBB & whole house book etc that external was the only sensible way. If rather more expensive and difficult.

    Hope it all helps.


    • Chuck
    •  

    • Oct 24th 2008

     

    If you google on “wimpey no fines”, you should get over 500 hits, some of them show the benefit of EXTERNAL insulation. As far as I could see no sites detail any internal insulation systems.
    FFF


    • JohnDoe
    •  

    • Oct 27th 2008 edited

     

    Thanks everyone for your information.

    <blockquote><cite>Posted By: Walker</cite>Foam backed plasterboard (with the foam faced with foil) is going to give you much better levels of insulation than any wet plaster at that thickness. Nearly al come with a ‘feather edge’ which means rather than plastering over the top you (carefully) fill the join between boards until level with the rest of the board – then decorate on top. Depending on which product you go for the thicknesses run between 34-37 mm for the thinnest up as far as you like although beyond about a 50mm thickness of insulation it is hard to fit. does 35mm include your existing plaster or is that with it removed?

    Price should be under £30 (+VAT) per board (although like all things getting more expensive all the time)which come as 2.4 X 1.2 m sheets (feather edge on long side).

    Some links:

    <a rel=”nofollow” href=”http://www.insulateonline.com/”> http://www.insulateonline.com/</a>
    <a rel=”nofollow” href=”http://www.celotex.co.uk/”> http://www.celotex.co.uk/</a>

    There are other manufacturers!

    I am a bit concerned about your ‘rising damp’ comment. That aside you would be well advised to surface mount all the pipework if only to make sure that your insulation forms a complete layer over the external wall. If it is not continuous you will be left with cold spots where condensation could form and cause problems.

    Keep asking questions before you jump!

    ‘Ventilation WILL cure condensation’ Tony – an uncharacteristically definite statement.</blockquote>

    There is no rising damp problem. I think you misunderstood my comment which was a description of the gap below the plaster which should be present on all plastered walls to PREVENT damp from rising into the plaster. It is that gap below the plaster on the wall that the hot water pipes go to my radiator on the rear of the lounge and was mentioned as I thought it might be needed to taken into account if a thermal board was added to the wall(s).
    Thanks for the links, I will take a look at what is offered on those sites.

    <blockquote><cite>Posted By: JJJ</cite>Is it the no-fines type where there is an infill board between the front window and the underside of the first floor window? No fines was a type of construction introduced about 50 decades ago and is, more or less, what it says in concrete terms except that, with the no-fines came very low cement contents. This means that it has a very low strength compared to ordinary concrete.

    First rule of insulating most ‘no fines’: Do not insulate internally.</blockquote>

    No, there is concrete above the windows. There were infill type boards, actually just uPVC panels on most of the houses around here, below some of the windows but the front lounge one has been removed and has been bricked up. There are slates below the kitchen and bathroom windows which I believe is not concreted and the kitchen is immediately below the bathroom. The main bedroom and rear kitchen have these uPVC panels below the windows.

    <blockquote><cite>Posted By: jon</cite>Hi Walker

    Sorry about that: 50 years. The no-fines typical designs have their floor plates connected through to the external walls (usually in one direction with the other tied in flipping from front to back) and can have some of their internal walls (particularly in and around the stairwell) framed off these members: If you put internal insulation in then you transfer the condensation point to the bearing locations for the first floor and roof plate.

    Would keep you warm for a few years but won’t be much consolation when the perimeter support for the first floor and roof starts to rot!

    There may be exceptions: Depends which type IcanDoit has. And particularly, is it an ‘end of terrace’?

    JJJ</blockquote>

    As stated in my first post, it is a Mid Terrace with 3 Beds and the property was built in 1964.

    The joists are connected to another large joist on the Party wall as you can see in the picture. There is no connection to the front wall although there does seem to be something wooden that does not go into the front wall, judged to be wood by scraping at it with a screwdriver, immediately below the large joist as marked in the picture but it’s thickness could not be that great as there is plaster board on the ceiling below. Unless it is just a lip and a large area goes across the party wall. The joist that is close to the front wall does not have any contact and is 1 and three quarters Inches away from the concrete, plaster would reduce that gap by approx half an Inch.

    I do not know how the large joist against the party wall is fixed in place. I have no building knowledge on this matter and did wonder how it was fixed. As to my homes construction, there are no soffits, only a fascia, which was originally wood which sits right against the front of the house with no overhang, see the third picture. The stairs are in the centre of the property running from the back to the front of the property. The stair well does have one fixing into the front wall by means of a metal bar which fixes into the joist that runs parallel to the stairs. There are house bricks either side of the stairs which help support the upstairs floor joists, with breeze blocks built on top of the joists/floorboards to form walls to separate the upstairs rooms. There is some white polystyrene foam used in my home underneath the plaster which I have seen in a number of places so there is some insulation as part of the original build.

    External insulation is out of the question as the cost is simply too great.

    The photos are first a quickly drawn plan of the lower ground which is not to scale.
    Next is a photo of the outside taken from the estate agent sales literature as it was too dark to take a picture. The front and back porches have both been replaced.
    3rd picture shows the small bedroom in the front of the house and shows how the joists are fixed. If anyone knows anything about how they are actually fixed I would like to know.
    4th picture is the corner section showing something made of wood marked with a white X and the arrow marks the end of it. I don’t know what this is. It has been mentioned above.

    Houseplan.jpg
    Home outside.jpg
    Joist Mounting1800x600.jpg
    Corner section.jpg


    • JJJ
    •  

    • Oct 28th 2008

     

    “External insulation is out of the question as the cost is simply too great.”

    Good luck with your project


    • TTMan
    •  

    • Oct 29th 2008

     

    Can you afford the cost of not doing it — this will be much greater.


    • Johndoe
    •  

    • Oct 29th 2008 edited

     

    Do you think that the type of build that the house has means that internal insulation is not possible?

    As I said there are no fixings to the front wall apart from a small metal bar that helps support the joists from the stair well, so what effect could insulating that front wall have on my property?

    =====================================================================
    <blockquote><cite>Posted By: jon</cite>Hi Walker

    Sorry about that: 50 years. The no-fines typical designs have their floor plates connected through to the external walls (usually in one direction with the other tied in flipping from front to back) and can have some of their internal walls (particularly in and around the stairwell) framed off these members: If you put internal insulation in then you transfer the condensation point to the bearing locations for the first floor and roof plate.

    Would keep you warm for a few years but won’t be much consolation when the perimeter support for the first floor and roof starts to rot!

    There may be exceptions: Depends which type IcanDoit has. And particularly, is it an ‘end of terrace’?

    JJJ</blockquote>

    ====================================================================

    From reading your comment, this does not seem to apply to my home as the joists are not connected to the external wall. So would there be any danger from condensation from insulating the internal front wall?

    Can you tell me how that large joist is fixed to the party wall from that photo?


    • TTman
    •  

    • Oct 30th 2008

     

    Looks like all the joists are notched into a trimmer that runs parallel to the party wall. The trimmer must bear on g/f walls I think.


    • Walker
    •  

    • Oct 30th 2008

     

    Yes looks like your joists are notched in ans resting on that batten at the bottom and the lot must be sitting on a wall. I would assume your downstairs rooms are narrower than your upstairs ones -either that or the plaster is holding them up. It certainly looks very hard, from your photo’s to approach insulating internally and be reasonably sure of protecting your structural timbers from condensation problems.


    • JJJ
    •  

    • Oct 30th 2008

     

    If you intend to insulate internally, I think you need professional advice rather than trying to come to a solution on a site like this.


    • Jamie
    •  

    • Oct 30th 2008

     

    Jon is right I think, internal insulation is a bit tricky: cold bridges, interstitial condensation, rot, mould etc, however dipping into this forum at the very least allows you to aske the right people the right questions.

    J


    • JohnDoe
    •  

    • Nov 3rd 2008 edited

     

    <blockquote><cite>Posted By: TTman</cite>Looks like all the joists are notched into a trimmer that runs parallel to the party wall. The trimmer must bear on g/f walls I think.</blockquote>

    ——————————————————————————————–

    what is g/f short for in your post above?

    ——————————————————————————————–
    <blockquote><cite>Posted By: Walker</cite>….I would assume your downstairs rooms are narrower than your upstairs ones -either that or the plaster is holding them up.</blockquote>
    ——————————————————————————————–

    It must be the plaster lol as the downstairs walls are the same width as the upstairs as I have a small piece of plaster off the wall in the lounge below so a TV cable could be routed into the small bedroom and I can see up into the small bedroom a short distance and the wall looks flat. You can see the black TV aerial cable coming through the joist.

    I am looking for someone involved in insulation to speak to, to try and find out more information and the way forward.


    • wackey
    •  

    • Nov 3rd 2008

     

    JohnDoe. I insulated my (1930s) house with 35mm phenolic foam boards and it worked very well. I was only there 13 years, but nothing went rotten in that time, but then it did have a narrow cavity so is not the same as yours. I took all the plaster off downstairs and glued the boards on – this reduced the amount that rooms got smaller to a trivial amount. I could give various useful detail advice about this, but I think you need to work out if that is the right way to go or not first.

    In general this is a good plan, however it does sound like with your solid walls you do have potential problems which mean it might be a bad idea in terms of long-term wood structure. None of us like paying for building control, but in this case you may well get your 100 quid’s worth because they will be familiar with the local construction and may well be able to confirm whether or not internal insulation is a good/bad/terrible idea. It’s true that external costs quite a lot more, and is harder to DIY, but it may be that or nothing, and if so you just need to do it in sections as funds become available. If DIYed it shouldn’t actually cost that much more as the insulation is cheaper (EPS/XPS vs PUR/phenolic foam), you need about the same area, and the ony hard bit is the rendering.

    It will produce a better result overall (no gaps, no condensation risk, no internal space used, more thermal mass).


    • TTman
    •  

    • Nov 3rd 2008

     

    g in g/f = ground (floor walls)


    • Simmo
    •  

    • Nov 6th 2008 edited

     

    If you need to go external (which is the recommended route for No fines) – you can over clad the insulation with render, timber, or brick slips, or a combination. If you use timber, a competent DIYer with drill, screwdriver and [hired] platforms should be able to do the job. You could even stick on some brick slips in places to give a [fake] brick built look. 

    One thing to be aware of – the EST are about to launch a new competition in December called Green Neighbourhoods. There’s £10 million of funding to go to 100 communities with “hard to treat” homes which would specifically include wimpy’s (and all solid wall properties), plus those living off the gas grid, or with solid fuel/oil heating. So that’s £100,000 per community up for grabs. IF you get talking to your neighbours now, you might have them interested enough to put in a bid. You have to commit some of your own funds which may be the stumbling block, but sometimes rules for these type of bids allow volunteered hours to count as matched funding.

    With a bit of design (or just look at most new apartment blocks) you should be able to make the area look as if it was built in 2008, rather than 1950 and increase the value of your houses by about 30%. 


ReplyQuote
  
Working

Please Login or Register