LeanTwo Posted October 21, 2016 Share Posted October 21, 2016 I am embarking on a kitchen/diner and repair project on my home that will require the installation of new/replacement windows and a bi-fold or French door. My property is a grade two listed building so my planning/listed building consent is conditional. The conditions are that I use wood for the construction of windows and doors and that they are painted white. They will have to have Georgian glazing bars and these will have to pass through the window so no stuck-on bars will be permitted. Each pain will have to be an individual unit such as the Wescountry Heritage range http://www.westcountryglass.co.uk/westcountry-heritage My application can be seen at https://planning.eastdevon.gov.uk/online-applications/simpleSearchResults.do?action=firstPage I am contacting joiners at present and have had a number of different suggestions as to the type of timber to be used. The suggestions include: Accoya Douglas Fir European Oak Utile Idigbo Baltic Pine/Scandinavian Redwood I have contacted the Wood Window Alliance http://www.woodwindowalliance.com/, which is already providing me with some good information. I would be grateful for any views on the suitability of timbers in my list or alternative suggestions. Also any links to useful sources of information or forums would help. Many thanks in anticipation! Link to comment Share on other sites More sharing options...
Crofter Posted October 21, 2016 Share Posted October 21, 2016 Welcome to the forum. The insistence on separate little panes is going to be a pain (sorry...) as it will cost more and leak significantly more heat. I'm no expert of different species of wood, but the list you give is a very wide range in terms of cost. Pine, redwood, and douglas fir will all be comparatively cheap but less durable than, say oak, which will be much more expensive, in my experience. As an aside, I wonder what your planners wood make of a modified wood like Kebony or Thermowood? Link to comment Share on other sites More sharing options...
gravelld Posted October 21, 2016 Share Posted October 21, 2016 Can you get glazing bars that are thermally broken? Look into whether cross laminated timber is permitted, assume so as it should look the same. Better than solid timber. You will want a construction that has its thermal break between the timber sections. Also look into engineered wood. Personally I would not go for a softwood (although it might depend on the exposure of the house). Link to comment Share on other sites More sharing options...
DavidFrancis Posted October 21, 2016 Share Posted October 21, 2016 I've seen one manufacturer (can't remember which one) that gave a much longer guarantee on treated softwood windows than they did on hardwood. I think the longevity of windows is as much (and maybe more) down to the detailing, installation & finish as the type of wood. I quite like the idea of dry-glazed windows with a ventilated bottom bead over a bottom rail cut at an angle (to drain water away). 1 Link to comment Share on other sites More sharing options...
Gone West Posted October 21, 2016 Share Posted October 21, 2016 Several years ago I saw engineered timber windows where the timber was laminated with layers of cork. That would reduce thermal bridging and may still be acceptable to the planners. Link to comment Share on other sites More sharing options...
gravelld Posted October 21, 2016 Share Posted October 21, 2016 1 hour ago, DavidFrancis said: I think the longevity of windows is as much (and maybe more) down to the detailing, installation & finish as the type of wood. I think you might be right, I was a bit hasty. Link to comment Share on other sites More sharing options...
mafaldina Posted October 22, 2016 Share Posted October 22, 2016 I think you will find that what they object to is glazing bars stuck on on one side only. I had this problem on a listed house and they let me install french windows with the glazing bars stuck to both sides so it looked like they went right through. Proper Georgian period glazing bars are much thinner than the more usual Victorian style ones that most people/manufacturers use. We had to copy the ones that were in the existing windows, installed c.1770, made from yellow pine and still intact. Go for high quality pine, much more resilliant/longer lasting than any hardwood. Link to comment Share on other sites More sharing options...
LeanTwo Posted October 24, 2016 Author Share Posted October 24, 2016 (edited) Many thanks for all of the replies. The requirements of planning authorities appear to vary. Some permit glazing bars that are mounted inside and out to give the appearance of a straight through bar and others do not. Whilst this thread is not about this issue, I do think it is inconsistent and unfair. All planning authorities should be following the same policy. My planning authority is insistent about fitting individual panes and straight through glazing bars. They will not approve mounted (stuck-on) glazing bars. I have discovered that doing this will result in much less satisfactory insulation. Insulation is very much part of the building regulations so the planning authority appears to be pulling in two contradictory directions. I will check out the thermal break issue with the planning authority. I guess this means including a good insulating material in the construction to prevent heat conduction? The experience of mafaldina is interesting in that the planning authority allowed stuck on bars in a Georgian house for the French windows. The width of the glazing bar has been discussed with the planning authority and they appear to have given the green light to a 24 mm wide bar. I will approach them on modified, cross laminated and engineered timbers (is there a difference between these terms?). Some feedback that I have had from joiners pulls me in different directions! Some have criticised certain timbers in certain ways. Examples are that Douglas Fir has an open grain so I guess they are inferring that it will absorb water. Some say a hardwood such as oak will move, which will be a problem with so many small pains. Other advice is that it's the external maintenance that really matters and a regular, yearly inspection and painting, if required, will overcome all issues of what timber is used. There are a number of other factors that will go into my decision as to which supplier to use, including joinery quality (I'm going to try and see examples of all products), draft-proofing, window furniture, delivery time, finishes and of course, price! I will be doing as much work as I can, myself on the project so any "how to" guides would be helpful, if you know of any. For instance, I guess there are various ways of fixing the window frame within the aperture and and various ways of sealing between the surrounding block-work and the frame? Are there any other good sources of self-build information, specialist forums etc? Any further thoughts? Edited October 24, 2016 by LeanTwo Spelling mistake! Link to comment Share on other sites More sharing options...
Crofter Posted October 24, 2016 Share Posted October 24, 2016 Planners are not interested in enforcing building regulations- that's the job of building control, who are a completely separate entity! Hence as you say the requirements pull in two different directions. 'Modified' timber means an almost semi-synthetic material, which started life as some form of wood but has been treated either through application of heat or via a chemical process (e.g. naturally occurring oils, acids etc). These are a fairly new invention and could be a big thing in the future, but they are expensive. Engineered and cross laminated timber are a completely different beast, being normal wood that is shaped and glued together to create something stronger and more dimensionally stable than a single piece of wood. Link to comment Share on other sites More sharing options...
LeanTwo Posted October 24, 2016 Author Share Posted October 24, 2016 ...thanks for the swift response and clarification Crofter. Link to comment Share on other sites More sharing options...
PeterW Posted October 24, 2016 Share Posted October 24, 2016 37 minutes ago, LeanTwo said: I will approach them on modified, cross laminated and engineered timbers (is there a difference between these terms?). One piece of advice on this ... DON'T ask the planners ...!!! Other than "white painted timber" they cannot tell you what to use if it's not going to be seen !! Use what is best for you from an economic and longevity perspective and just give them what they want - a white painted timber window ..!!! Link to comment Share on other sites More sharing options...
mafaldina Posted October 25, 2016 Share Posted October 25, 2016 On 10/24/2016 at 10:55, PeterW said: One piece of advice on this ... DON'T ask the planners ...!!! Other than "white painted timber" they cannot tell you what to use if it's not going to be seen !! Use what is best for you from an economic and longevity perspective and just give them what they want - a white painted timber window ..!!! That's not entirely true I'm afraid. It is true vis à vis the normal planners but not Listed Building officers. If a building is grade 2 (any grade really) listed it includes all elements, internal or external, even down to door handles/light switches/wall coverings/lighting etc., if you are unlucky. If it is not listed but in a conservation area then it is, usually, just the exterior (often only the facade) that they are concerned about. The best is to set up a meeting with your BCO and Conservation officer and negotiate. You can work this both ways. Either to dispense with some elements of BC – I managed to get an open 4 storey staircase (without sprinklers or fire protection) through by using Listed Building against BCO (see photos), you can work it the other way too as I did with the glass doors. Link to comment Share on other sites More sharing options...
PeterW Posted October 25, 2016 Share Posted October 25, 2016 You need to be very careful with Grading and its uses - I advised on a G2 recently where the Council were saying they "needed" to be consulted on "all aspects" of the changes. Politely but firmly the council were advised that we would not be consulting them when it came to replacing floorboards... Grading ONLY applies to the items listed in the grading notices - I looked at a house where only half of it was graded as there had been an extension added post the grading and the extensions was not graded. I've also seen one where the external garden wall and iron railings were listed but the house was not ! Listed Building Officers and Conservation Officers love to think they have carte blanche to insist on you doing things that they have no jurisdiction over. The first place you should start is with the grading notice for the property - that should list out what has to be considered when you are doing any work on the property. Link to comment Share on other sites More sharing options...
mafaldina Posted October 26, 2016 Share Posted October 26, 2016 Peter, I beg to differ. https://historicengland.org.uk/advice/hpg/has/listed-buildings/ Link to comment Share on other sites More sharing options...
PeterW Posted October 26, 2016 Share Posted October 26, 2016 OK - this is the key paragraphs from the Historic England guidance and I've been round this loop with both G2 and G2* buildings : You will need Listed Building Consent for all work to a listed building that involves alterations, extensions or demolition and will affect its character as a building of special architectural or historic interest. Your local authority can help you to determine what the special interest of your home is. The requirement applies to all types of work and to all parts of the house covered by the listing if its special interest will be affected. The list entry will identify the principal building or buildings that are listed. These will be identified by the formal list entry and not the narrative description, unless there is ambiguity in the list. The whole of any principal building is listed, including the interior. These rules may mean that considerably more may be protected by the listing than is obvious from the list entry alone and there can often be considerable uncertainty as to what is covered. This apparent unhelpfulness in the rules is mitigated somewhat by the fact that listed building consent is only required if works affect the special interest in the relevant structure. It may be unclear whether a structure is protected, but it may be clear it holds no special interest even if it is. Group value should obviously be considered in assessing the special interest of ancillary buildings. Back to the OP comment - they have asked for white painted timber windows - they CANNOT say what that timber is. Link to comment Share on other sites More sharing options...
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