navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address - following recent spam/hack attempts on the forum, all security is set to "high", and "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Timber suspended floor INCREASING height with Underfloor Heating  (Read 931 times)
Bikerzz
Jr. Member
**
Offline Offline

Posts: 83


« on: January 03, 2019, 07:55:56 AM »

Morning all

Im converting a 1967 property to be as energy efficient as possible, it will be my forever home for 30 years till I retire and downsize, no children yet and a Welsh Valleys Mrs so very accommodating with smashing things up! House is a mess already and needs rewiring, plumber and decorating anyway.

Property was extended in 1994..... badly (Ground floors on various height), the extension is block and beam, the original part of house timber suspended.
Ive dug out the screed (in process in some rooms still), then will put down Celotex type insulation, then 50mm liquid screed with pipes, to maximism insulation I will be increasing floor height throughout house which is fine as doors have HUGE frames and voids till the lintels. Which means the original floor level needs to rise 50mm ish on the timber suspended.

I will be using water UFH on the timber suspended floor, so any advice on best way and how to increase floor height on the timber without adding in 50mm ply which would prob be very insulating in the wrong place? Which system would you use on the timber suspended bit? Can someone list the build up they would do? Do I put a thinner play over and a thin liquid screed on that (I guess I can do a 25mm layer liquid screed with no pipes?)

Screed
25mm ply
Timber tops with ali spreader plates and 16mm pipes
Main timber Insulation (100mm Celotex)
Air Gap

The Block and Beam will only get 50mm insulation in some rooms but Ive seem systems with NONE and even 30mm and being fine, some will be upto 85mm, so will just find the best R rated insulation I can for the block and beam.

Cheers
Logged

Triple Glazing.50mm CWI.
offthegridandy
Hero Member
*****
Offline Offline

Posts: 968



« Reply #1 on: January 03, 2019, 09:34:43 AM »

Good morning Bikerzz.  Good to hear about your project.

  I personally have great reservations about the efficiency of UFH with timber floor. We are in a barn conversion which I carried out some 15 years ago.  The only thing that I have ammended since the main body of work, was to redo one floor that had timber finish.  We have wet UFH  right through the ground floor and one area had timber finish.  The boiler would be cycling on and off trying to warm the one room (timber floor).  After a couple of years I ripped the floor up and redid with screed.  A lot of messy work but since then the UFH has been a dream.

If you do stick with timber finish you must ensure that there are NO air gaps between the underside of the timber and the sub floor or the efficiency will drop right down.
#
If you are stripping right back to the joists on the ground floor; could you install a beam and block floor and maintain a solid floor through out. You could bring up a couple of dwarf walls to put the beams on and then the blocks then the insulation and pipes and screed and with care you could get your levels through to match the extension.  If you lay beam and block a tip is to run in a wet sand cement wash across the face of the blocks once inplace.  The runny mix seals all the little gaps between the block edges before you put in the insulation. And do tape the joins carefully on the Celotex, buy the proper stuff.
 
Don't know if you've seen somat like this, it's a guide to using "PUG" to fill the voids around the pipe. http://www.wundafloorheating.co.uk/wp-content/uploads/2017/02/F05T-Pug-Screed-System.pdf

There are also past threads here on Navitron.

https://www.navitron.org.uk/forum/index.php?topic=19329.0


Cheers.

Andy
Logged

8 KVA Lister TS2 Startamatic Genny
24 Volt 1000amp battery bank
Outback VFX3024
4.6 Kw PV array permanently ground mounted
Outback Flexmax 80
2 X Flexmax 30 PV CC
2.5 Kw wind turbine H Piggot design 4.5 Mtr Dia
12 Mtr free standing Tower.
u/floor heating from oil boiler cross linked to 12 Kw
marshman
Hero Member
*****
Offline Offline

Posts: 899


WWW
« Reply #2 on: January 03, 2019, 11:24:24 AM »

I have "wet" UFH. It is a renovated farmhouse with parts dating back to the late 1600's. Ground floor is concrete slab, 50mm "jablite" (polystyrene) insulation  [renovation was done the mid 80's an celotex was not as ubiquitous as it is now]. The heating uses 20mm Wirsbo (now Uponor) PEX pipe. It sits in aluminium spreader plates in the polystyrene (so only 25mm insulation below the pipes). On top are 25mm thick "pitch pine" floor boards.  The first floor just has the aluminium spreader plates filed to battens that cross the joists. Again 25mm pitch pine floorboards cover this.  The UFH pipes are on approx 12" centres. All floors apart from the kitchen are covered with carpet and underlay. Kitchen floow is 25mm chipboard with a vinyl (lino) finish. The system works a treat and is so economical to run. The down side is a slow response time, but we have the heating running 24/7 in the heating season so response is not an issue.  The system used to be driven by a wood boiler but I changed to a GSHP 3 years ago.  So from my point of view / experience a timber finish is not an issue.

Our previous house had a 50mm screed with UFH pipes buried in it (again 20mm PEX on 12" cebtres) on the ground floor - insulation was 2 layers of 2L2 - bubble wrap and silverpaper!. Upstairs was aluminium spreader plates and floor boards. Again system worked well and was very economical.

I think the problems occur when you have a mixture of solid (screed) floor and timber floor with spreader plates on the same manifold as the running temps need to be different.

Roger




Logged

3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
Countrypaul
Hero Member
*****
Offline Offline

Posts: 1376


« Reply #3 on: January 03, 2019, 12:29:30 PM »

I renovated our dormer bungalow and we finally moved in this September past. The orginal floors were a mix, some were concrete with tiles - unfortunately concrete directly onto the ground, some were suspended wood - unfortunately some sections missing and just covered with laminate, the joists were generally 4x2 with dwarf walls (no foundation), one section wooden joists filled with concrete and then boarded over and we had to add some floor for the extensions and change in height where the garage was. Given we are on a fairly significant slope beneath the floor it varies from about 12" to about 72" space, so a suspended floor was the most realistic option. We were going to make the new with Beam and Block and then spray seal underneath the suspended wooden floor - this was before we realised the concrete floors has no DPM or insulation.  As usual with a renovation we discovered things we wish we hadn't, so more and more of the floor got changed to be B&B leaving a smaller and smaller suspended wooden section. I looked at the option of replacing the suspended wooden floor completely with B&B and decided the cost was not that high but it eliminated many other probems and would be much simpler to progress with that we went with that option.  So instead of 4 sections of B&B linked with suspended wooden flooring we have an entire B&B ground floor. It made putting UFH heating in much simpler, avoided repairs to the wooden floor, separate insulation process to the wooden floor (which would have also required excavating underneath as there was insufficient space tp spray insulation in a large section imroved safety since in one place (now middle of the lounge) there was a dwarf wall that on ground that had been excavated out 2 feet down right beside the wall (as there were 2 x 300 gallon oil tanks under the floor!). As a result we have a well insulated floor with UFH that has no changed of height, floor behaviour (kids jumping up and down can cause curious effects based on our previous place) and keeps the whole place warm. The water temperature for the UFH is run at or below 25C. We had to put some dwarf walls in a couple of places, but where our extentions were the old walls were used. Our make up is Beam and Block, 1200g DPM, 120mm PIR insulation, 300g VCL, UFH pipes at 150mm centres, 70mm sand and cement screed. Where the floor touches the outside walls we have 50mm pur but on internal walls there is only 25mm beide the screed, this means the PUR is covered by the plasterboard and skirting in most cases - some outside walls are SIPS and battened (25mm) before the PB and skirting, older brick walls are battoned 50mm with rockwool between before PB.

If you have the choice I woud go with Beam and Block and try and do the whole floor as one. If you need to retain the suspended wooden floor, then one option is to remove the floor boards and fit them between the  joists lower down, allowing for insulation above between the joists and a layer of insulation over everything before a sand and cement screed. Avoids the probem of wood insulation above the screed, but may require additional support for the joists.
Logged
Bikerzz
Jr. Member
**
Offline Offline

Posts: 83


« Reply #4 on: January 04, 2019, 10:16:09 AM »

Thanks Guys

After getting all worried this was going to be a nightmare I sat down and had a think (or rather my uncle builder and I had a chat, he lives miles away so cant do the work).
I will prob have 20 or 25mm floor boards on the timbers, then 10mm grout, then 10mm tile so all is oki as I also want to raise 45-50mm. So I can

Insulate under timbers with 100mm rockwool
Insulated between timbers with 100mm Celotex
25mm Ply on timbers
16mm Poly Pipe with 60-70mm liquid screed

All is good!

I panic too much!

Sheldon






Logged

Triple Glazing.50mm CWI.
Countrypaul
Hero Member
*****
Offline Offline

Posts: 1376


« Reply #5 on: January 04, 2019, 01:57:32 PM »

When I was looking at liquid screeds, most I talked to said that a liquid screed should be thinner and recommended extra insulation and a 40-50mm liquid screed. In the end we ended up with a sand and cement screed because we couldn't get a liquid screed delivery close enough, and even teh S&C screed had to be deliverd a mile away and transported in small amounts to site.

You may want to check whether a thin layer of insulation under your screed with a thninner screed might be more bneficial.
Logged
Bikerzz
Jr. Member
**
Offline Offline

Posts: 83


« Reply #6 on: January 04, 2019, 02:02:45 PM »

Cheers Paul

Yes I did know about this so maybe another 20mm of celotex on top too, then 45mm liquid screed, brilliant, Thank You
Logged

Triple Glazing.50mm CWI.
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!