Home » Forum » General discussion

Sempatap: DIY product to insulate sold walls

Dear all

I wanted to pass on some information about a DIY product available to internally insulate solid walls.

Last week I met with Linzi Bagshaw from Mould Growth Consultants who produce "Sempatap Thermal" - a 10mm thick foam backed "wallpaper" which can be used to reduce heat loss through external solid walls. The product is Energy Saving Trust recommended.  Rolls (12.5m x 1m) cost from £145 + £25 for adhesive and £5.70 for sealant.

Linzi would be happy to attend events or meetings to tell you more about the product:

Linzi Bagshaw 

Energy Efficiency Project Manager 

MGC 

McMillan House 

54 - 56 Cheam Common Road 

Worcester Park 

Surrey 

KT4 8RH 

Tel: 020 8337 0731 

Fax: 020 8337 3739 

Mobile: 07798 837832 

Email: linzi [dot] bagshaw [at] mgcltd [dot] co [dot] uk 

Website: www.mgcltd.co.uk

 

Jessica

Jessica Binks 

Energy Strategy Officer 

Sustainable Services Division

Environment and Housing Department

Southwark Council

Originally submitted by jessica on Tue, 11/05/2010 - 9:07am.

Last update on Wed, 12/05/2010 - 1:42pm.

tags:

#1

Submitted by anna on Tue, 11/05/2010 - 2:16pm.

Thank you Jessica.

Sempatap has been available for many years now.  [Indeed, it was my dissatisfaction with the "sempatap solution" 6 years ago that got me really actively engaged in energy issues.]  The main problem with it is that most people don't want squishy walls - makes them feel they're living inside a padded cell - or that if the sempatap has been slightly reinforced, it isn't sufficiently sturdy to have such outlandish and rare objects as pictures, shelves etc attached to the wall.  However, it may be useful in some instances.

Presumably you do know of other producers or distributors of sempatap or similar?  We'd be very interested to receive information about them too so that, should Peckham Power decide it might be useful to have a demonstration, we are able to pursue a range of contacts rather than be passively beholden to only one.

Kind regards,

Anna

»

#2

Submitted by jessica on Tue, 11/05/2010 - 2:33pm.

Hi Anna

Yes, I'm aware Sempatap has been around for a while - Southwark have fitted it for some time as a remedy to mould growth and I actually have some in my own house!

As far as I know Mould Growth Consultants are currently the only supplier of Sempatap in the UK at the moment. The only similar product I have heard of is Walltransform Warm-a-wall, which requires a skim plaster finish:

http://www.walltransform.co.uk/

Best wishes

Jessica

Jessica

»

#3

Submitted by Jack on Tue, 11/05/2010 - 6:25pm.

Many thanks for this.

 

My two cents:
 
Sempatap is pretty controversial stuff.  It's an "EST recommended product" (and the 10:10 campaign have adopted the EST's recommendations).  But Sempatap gets pretty slated on the Green Building Forum (which is mostly populated by green refurbishment professionals). I've heard it said that strictly speaking, installing sempatap to an entire wall contravenes building regs because building regs require you to achieve a u-value of 0.35 if you modify more than 25% of an external wall but 10mm of Sempatap over a 9" solid wall only gets you to a u-value of 1.47 (although it's not entirely clear if gluing Sempatap to a wall qualifies as "modifying" it).
 
Personally, I think Sempatap is a bit of a waste of time.  Installing Sempatap is perhaps 50% as much work as installing "proper" insulation (e.g. 60mm of Kingspan) but offers 8% the performance (Thermal resistance of 10mm Sempatap = 0.213 m2K/W; 60mm of Kingspan = 2.61 m2K/W).  If you're doing all that work then you might was well go for a "proper" insulation like 60mm of Kingspan.
 
Some numbers (I've calculated the reductions in terms of percentage decrease in energy loss to aid comparison with the target of cutting carbon emissions from our housing stock by at least 80% by 2050):
  • U-value of uninsulated 9" solid wall = 2.1 watts per square meter per Kelvin
  • U-value of 9" solid wall plus 10mm sempatap = 1.47 W/m2K  (31% decrease in energy loss compared to uninsulated solid wall) (many thanks to Jessica for the updated figures)
  • U-value of 9" solid wall plus 10mm Aerogel (high performance but very expensive) = 0.8 W/m2K (62% decrease in energy loss)
  • U-value of 9" solid wall plus 32mm Aerogel = 0.34 W/m2K (satisfies building regs) (84% decrease)
  • U-value of 9" solid wall plus 60mm rigid foam = 0.34 W/m2K (satisfies building regs) (84% decrease)
Dry-lining using Kingspan is, admittedly, slightly trickier than applying Sempatap.  But it's something a competent DIYer should be able to do.
 
So yeah, Sempatap is better than nothing.  Covering the nation's houses in Sempatap might get us close to our 2020 emissions targets.  But then all the sempatap would have to be ripped out and replaced with decent insulation in order to hit our 2050 targets!.
 
I don't mean to put a downer on this.  Just trying to provide some comparisons.
 
Thanks,
Jack

 

»

#4

Submitted by Anonymous (not verified) on Thu, 29/09/2011 - 9:09am.

Hi Jack.

Thanks for your comments I have just worked out what it will cost me to fit sempatap to my semi ( 700 quid) and I was not sure of the benefits. I don't have a mouldy house, so I was looking for a significant reduction in heating bills. It is good to know there are other products on the market other than sempatap.There does not seem to be any grants towards the cost of installing this type of insulation, only cavity wall. I was told by my local energy saving trust that there might some next year, but I willnot hold my breath.

Thanks

Aid.

»

#5

Submitted by JamieG (not verified) on Mon, 12/12/2011 - 2:23pm.

 I can see both sides of this debate.  On the one hand, my circa 1900 solid walled semi needs 'something' on the internal walls to improve efficiency and remove condensation issues.

Adding 50-60mm of depth to internal walls is a both a considerble invasion of space in small rooms but also means that I'd have to move door frames and replace a lot of furniture.  The project cost and inconvenience therefore becomes unrealistic so 'nothing' gets done.

Sempatap would solve the prime issue of mould generated by condensation, without having to rearchitect every room and provide a degree of insulation far better than nothing.

It's all very well having beurocrats devising new ways to improve buildings but it's consumers already under spending pressure in tough economic times who have to pay for the resulting actions.

The other thing that surprised me was that Sempatap appears to be offered directly to DIY installers at a discount equivalent to the grant based pricing of local councils, making the whole process of grant application redundant.  Or I am missing something!

»

#6

Submitted by Jack on Thu, 15/12/2011 - 10:58am.

 Hi Jamie,

All good points.  Installing Sempatap is certainly easier than installing foam-backed-plasterboard.  The only small suggestion I would make is that if 60mm is too much depth to lose then do consider one of the thinner foam-backed plasterboard products (like maybe 30mm?).

I've been slowly installing foam-backed plasterboard throughout our Victorian house. Doing it in our living room was an absolute nightmare (that project took literally two years - here are the gory details if you're interested).  But we also had 80mm of insulation installed in our "study" (spare room) and bathroom.  The bathroom now hardly needs heating - it heats itself sufficiently from the "waste" heat given off by the boiler (which is installed in the bathroom).  And the study is now so well insulated that I can warm it just by sitting in it with my laptop and LCD monitor.  The study isn't a big room (maybe 2m x 3m) and we were worried about losing too much space but it's turned out fine and I love how cosy it is now.

You can save a bit of money on foam-backed plasterboard products by buying "seconds" (just google for "seconds insulation").  I bought my insulation from PlanetInsulation - they did a good price.

But I totally accept your point that takes longer to install these products than sempatap, and time is short.

Best of luck with your project,

Jack

»

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Insert Flickr images: [flickr-photo:id=230452326,size=s] or [flickr-photoset:id=72157594262419167,size=m].
  • Web page addresses and e-mail addresses turn into links automatically.
  • Link to content with [[some text]], where "some text" is the title of existing content or the title of a new piece of content to create. You can also link text to a different title by using [[link to this title|show this text]]. Link to outside URLs with [[http://www.example.com|some text]], or even [[http://www.example.com]].
  • Allowed HTML tags: <a> <p> <span> <div> <h1> <h2> <h3> <h4> <h5> <h6> <img> <map> <area> <hr> <br> <br /> <ul> <ol> <li> <dl> <dt> <dd> <table> <tr> <td> <em> <b> <u> <i> <strong> <font> <del> <ins> <sub> <sup> <quote> <blockquote> <pre> <address> <code> <cite> <embed> <object> <param> <strike> <caption>
  • Each email address will be obfuscated in a human readble fashion or (if JavaScript is enabled) replaced with a spamproof clickable link.

More information about formatting options

CAPTCHA

This question is for testing whether you are a human visitor and to prevent automated spam submissions. If you were logged in then you won't have to do this tedious task.

Image CAPTCHA
Enter the characters shown in the image.