Draft proofing a suspended timber floor

If insulating under a suspended timber floor is not possible, how can you stop the drafts between the floor boards?

Looking on the Web is a great way to research the best way of doing something. Caramel Quin wrote a great blog some time ago looking at ways to draft-proof stripped wooden floors. http://www.guardian.co.uk/environment/blog/2011/dec/16/1.

Some timber and floor boarding companies had good blogs on the ‘filling the ‘gaps’  http://www.woodandbeyond.com/blog/three-methods-to-fill-gaps-in-wood-flooring/ but many are for where you have not yet sanded the floor.

I thought seriously about using wedge-shaped pine slivers http://oldpinecompany.co.uk/acatalog/About_Old_Pine_Slivers.html they are possibly the best and the most ‘green’ solution but I didn’t want to sand the floor again.

I needed to eliminate the draft but I wanted to retain the look of the golden pine boards broken by dark lines, which meant retaining the gaps. This stance eliminated using any kind of filler option, which can often fill both the gap and half the floor board.

Having considered all the options I opted for StopGap http://www.stopg-p.co.uk/ . It is thin V-shaped plastic on a roll that you push into the gap, down to the joist level and it opens out to fill the gap. It can be used to fill 1-8mm gaps in both floor boards and skirting boards. If you are going to re-varnish the floor this needs to be done before fitting the StopGap.  To ensure the StopGap works as efficiently as possible the gap between the floorboards need to be free from debris and any drips of old varnish cleaned off the sides of the floor boards.

I wanted to make the floor as draft proof as possible so to finish the floor I ran a strip of painted timber beading around the base of the skirting board and sealed this with an acrylic interior frame sealant.

The result; the ground floor is definitely less drafty and the room feels noticeably warmer.  The ‘under the floors board’ insulation option would have been better in terms of heat loss but it would have cost over £1,000. So I have stopped the drafts, kept my golden pine floor boards (some of which I have covered with rugs to give that real feeling of warmth) and the materials cost less than £150.

To move or to improve?

The housing market in the South East of England has always been strong but given the recent election, Brexit and events across the world we are in uncertain times and no one knows where the housing market will go next? It’s something we may ask ourselves when that inevitable question comes up “shall we put the house on the market and move or should we stay and improve?”

We all seem to need more space in our homes: an office at home is a work solution more of us are choosing and our families grow and need more room. Should we sell up and buy a bigger house, buy a property with development potential or improve our existing home?

Option 1: Move

Buying a new house is exciting. It gives us the opportunity to live in a new area, to see the town where we live from a new perspective and to meet new neighbours. Buying a new house can also bring new development opportunities, there are always properties advertised for sale that are ‘ripe for improvement’. You may also decide to move to a smaller home to reduce your outgoings.

Moving house is also one of the most stressful things we do; hopes and dreams can be dashed at almost any stage in the process. There is a substantial cost to moving. Dependent upon the value of your home, you’re unlikely to get much change from £20,000 just to move, and the costs could be much higher.

Option 2: Improve

Staying put and improving your existing home may not be as exciting, but it’s unlikely to be anything like so stressful. The £20,000 or more you would pay out just to move would go a long way to converting your loft or building an extension.

Whilst you home must firstly be the place you live it’s likely to be your most valuable asset and you may as well make the most of it. So it’s worth think about how you could improve your current home. Before you call the estate agent ask yourself “do I have to move, do I just want to move or could I stay put in my current home?”

Whichever option you choose, making the most of the development potential of your home is probably the most cost-effective way of increasing your living space.

Interested in option 2? Contact me for a free consultation on what could be possible with your current home or the development potential of your new one.

Insulating a suspended timber floor

My next task was to insulate the suspended timber ground floor.

I calculated that the gaps between my floor boards was equivalent to a hole 800mm by 800mm, no wonder it felt drafty. The floor boards on the ground floor are the original ‘pine’ boards, a beautiful golden colour. I wanted to retain them as a feature of the house so the only option was to insulate underneath them. The two ways to achieve this were either to lift all the boards and insert the insulation from above or get under the floor and insert the insulation from below. The floor was fixed firmly, it had been sanded and varnished already and lifting all the floorboards would have caused a lot of breakages and require re-sanding. The only option was to insulate and draft proof from underneath.

I removed a couple of boards in the hall, donned a boiler suit, goggles and face mask and squeezed under the floor – I could just move around, so it may be possible.

I now had to determine exactly what I needed to do. The Web has a number of good links covering insulating under a timber floor.




The aim is maximum insulation between the floor joists, using a fibrous insulation material that takes up the imperfections in the timber and that minimises the air movement around the insulation. The other objective is to stop the movement of air through the insulation and into the room but allow water vapour that may build up to escape. In addition; the insulation should not come into contact with any masonry walls but the gap between the joists and the foundation walls (usually about 50mm) needs to insulated and made draft proof, the air bricks from the outside need to be kept clear, cold water and central heating pipes below the insulation level need to be insulated (the void below the insulation will be much colder) and any electrical cables need to be prevented from overheating and kept free of insulation.

I needed to establish categorically if I could do all of this from underneath. There is a 400mm space between the bottom of the joists and the ground level but the joists rest on 100mm timbers so the working height is 300mm. I had to be able to crawl around underneath the floor for several hours completing the insulation and draft proofing work. I donned my boiler suit, goggles and face mask and after ten minutes established that 300mm was not sufficient room to do what was required – back to square one.

Passivhaus: German engineering for greener homes

Extending the Passivhaus methodology to all

I have studied to be a Passivhaus Designer. Whilst I am itching to get involved with my first Passivhaus I am very interested in the lessons we can learn from the methodology and how I can use this to the benefit of jobs where I’m not designing to the Passivhaus standard.

What is Passivhaus?

Passivhaus is a design and build methodology used to produce low-energy, superbly comfortable buildings. It was pioneered by German physicist Wolfgang Feist . In simple terms the high level of insulation, the super air tightness of the building and the rigorous attention to detail means that the heating demands can be as little as 10% of the heating required in a comparable building built to current UK standards.

There are thousands of Passivhaus on the continent, but in the UK there are only 100 or so newly built Passivhaus homes and a handful of retro-fits, which are existing buildings that have been upgraded to the Passivhaus standard. Passivhaus is a relatively new concept in the UK and build costs are said to be 10 to 15% higher than traditional build costs.

What can we learn from the Passivhaus methodology?

1.   More rigorous energy assessment

Passivhaus uses a planning/design tool that pulls together all the components of the building, enabling the designer to adjust the type, performance and/or cost of the components to achieve the optimum energy use of the building. It’s the most rigorous, accurate and detailed energy assessment tool  I have ever used and its wider use would significantly benefit any building job.

2.   Closer attention to detail and air tightness

A large part of the success of a low-energy home is to have well thought-through and detailed designs of the elements of the building where heat is lost. Passivhaus requires the architect to produce details for the junctions and for the structural elements that eliminate thermal bridges and do not compromise the air tightness of the building.

3.   Improved build quality

The third element is that of the build quality: the builder must understand and build to the architects’ details. A small number of builders are starting to build to these exacting standards, but the vast majority, whist not adverse to new methods of working, do not seems to know about or understand the physics behind these ‘new’ build methods.

4.   Better team working

The forth lesson is that all the team involved with the build (the client, architect, consultant and the builder) must work together. The team must understand the concept; know the reasons things are being done in a certain way, and work collectively to achieve the common goal. Not impossible, but not often achieved on a standard UK building job.

Interested in building a Passivhaus, in bringing your home up to Passivhaus standards or using the Passivhaus design methodology? Contact me for a free consultation.

Act now to stay warm and save energy next winter

The summer is here and the last thing any of us are worrying about is keeping our houses warm. Even if you’ve had a new insulated loft conversion done in the last couple of years, chances are the rest of your home could be better insulated.

Two quick insulation wins

I think of my own house and what I could do before next winter. The quickest and cheapest wins are insulating what is known in the business at the ‘opaque elements’ of my home: the exterior walls, the loft and the ground floor, and now, over the summer, is the perfect time to time to get it done.

1.   Insulate the wall cavities

I have considered the pros and cons of cavity wall insulation for many years and have still not done it. Looking at my energy bills over the last year, it’s a no-brainer and I have had it done. I’m not too close to the coast to be classed as “an exposed property”.

The cavity wall insulation was not without its problems. Downs Energy arrived to do the job but on opening up the cavities they found that some of them were full with rubble, well above the DPC level. Filling the cavities without removing the rubble would cause bridging of the damp proof course, so they had to be cleared. Several bags of rubble later and a couple of days labour (which was a cost to me) the cavities were clear and filled.

2.   Insulate the roof

Luckily, my loft conversion is already well insulated, but if you need loft insulation.  I’ve also insulated the ceiling of my flat roof, which has really improved the heat-retention. However, I will check the eaves and storage area in the loft to ensure it is up to the optimum insulation thickness of 270mm.

3.   Seal the floor

The final task I’m going to complete this year is insulating the ground floor . I have sanded and sealed the original timber floor boards. They are beautiful, but cold air rushes in through the gaps and it is often cold, even on a summer day. The problem I have not yet solved is how to insulate under the floor boards without lifting and re-fitting them: I can get underneath the floor but the space is only 400mm (1’ 4”).

Taking your insulation even further

Next year I will look into improving the energy performance of my single-glazed windows, probably by fitting Slimlite double-glazing units or internal secondary glazing. With two large bay windows (five sash windows in each) and four further large sash windows the refurbishment cost will be much more than what I’ll be spending this year!

If you need advice on what you can do to make your home more energy-efficient, contact me for advice or an energy assessment.

‘Modernising’ an unusual period feature

A first floor conservatory? Not a common feature in a house, but one that seems to be fairly popular in early 20th century townhouses in Brighton and Hove, and one I was pleased to help transform for 21st century comfort.

This conservatory faces south and west, fantastic for the afternoon and evening light. With its first-floor elevation it soaks up the last rays of sunlight when the ground floor of the house is already in shade.

The original conservatory was a softwood timber structure with coloured glazing in the windows and sides and an opaque glazed roof. The glazed roof had long been covered over with corrugated asbestos sheets and the roof and glazing leaked and the conservatory was cold.

The brief was to replace like for like but simplify the structure, open up the space to the rest of the house, make the new room as warm as possible (within the budget) and add an opening roof light for ventilation.

A new structure

The chosen solution was a sustainable hardwood for the structure, giving strength, durability and minimising movement. The conservatory was fabricated in David Salisbury’s workshop where the timber could be cut with precision and finished with three factory-applied coats of a micro-porous paint for longevity. This factory production meant that the on-site build time was reduced to just days.

Added light and warmth

The glazing units are low-energy double-glazed with special glass in the roof to cut down the heat gain in the summer.

For the technically minded the vertical glazing units are clear solar-controlled easy-clean glass combined with low-E glass and argon-filled sealed units with a U-value of 1.4 W/m2K. The roof has the same specification with the addition of azure solar-controlled ‘blue’ glass on the outside with a U-value for the glazing units of 1.1 W/m2K and a light transmission value of 59%.

The doors and brick piers separating the conservatory from the adjoining room have been removed and replaced with a steel stability frame, the dwarf solid brick walls lined with insulation and the existing timber floor has been renovated.

The work has created a beautiful, light, warm room that is very much part of the property but where you can get away from the hubbub in the rest of the house. You can relax there and look up to watch the clouds drift by and the seagulls flying overhead or it works as an office or occasional bedroom with a view.

Have an unusual feature in your home you need to repair or replace? I’ve extensive experience in renovating properties and working on listed building and in conservation areas. Contact me to discuss your project.