Thanks all for your comments - really helpful. I think this is the problem when you are dealing with a period property and adding a side return, how to incorporate all the things that would just happen if you were building from scratch. Our builder has now proposed recessing the soil pipe, approx 100 cms diam, into the outside wall with the water down pipe in front. His thinking is that it would be easier for us to access and also maintaining the aesthetics of the room. The builder is a tidy worker and either option is cost neutral so there is no saving to him. I wish I could post a picture but the only docs that I have are the plans with our details plastered all over them, so I will do my best to explain. The ground floor back of the house will be wall to wall and measure approx 5.5m wide. Looking at the property on the right there will be 3m wide by 2m tall bi fold doors and on the left 1.2m wide and 2m tall single solid pane of glass for the side return. So there is only a column of less than .5m between the solid pane of glass and bi fold doors available for use. The builder will use the column area to host the down pipe from the roof and the soil pipe will be recessed into the brickwork behind it. Note this soil pipe will supports 2 full bathrooms and 1 separate loo = all on upper floors. Also, there is a new soil pipe which will support the loo in the ground floor utility room. I am nervous of sounds inside the dining area especially as the dining table will be literally a foot from the proposed internal boxing covering the soil pipe. I have read lots on the internet maybe 60% say they have no noise from the soil pipe boxed in the room and 40% say it’s noisy. I have even seen a boxed soil pipe attached to a kitchen island and between appliances/cupboards – not ideal but there seems to be no reason why it can’t be placed anywhere. Thanks for reading and advice.

There is no right or wrong answer - and as suppliers and installers of award winning versions of both bifold AND sliding door systems we have no bias towards one or the other. Our teams install nationally, from Shetland to the Channel Islands...and everywhere in between. When we get asked this question by customers there are a number of initial things we would ask to try and make some recommendations - and we have written a blog all about these. Probably the most valuable question is realistically how often are you likely to have the doors fully open. Our SF55 aluminium bifold doors can be manufactured up to 1.1m wide and have an industry leading narrow sightline of 115mm (the amount of frame visible when closed) and over a 29' 6" run of 9x1m panels you will have 8 intermediate frames totalling 920mm of aluminium. We do two aluminium sliding door systems the Grand Slider (83mm sightlines) or our award winning theEDGE (narrow 24mm sightline) - both can take glass sizes of up to 3m wide so over a 9m run of 3x3m panels you will have 166mm of intermediate aluminium visible with the Grand Slider and just 48mm visible with theEDGE. So if your doors are closed more often than open there is significantly less frame than glass in sliding doors - maximising your views - however the trade off is that unless you opt for a pocket slider you are not able to open a sliding door completely to create a total 9m opening like you are with bifold doors - you would only open 6m of the 7m (or 6.75m if you went for four sliding door panels). In terms of thermal performance both SF55 and the sliding door systems can be double or triple glazed and achieve pretty similar U-Values and in terms of price the SF55 and Grand Slider systems work out to be almost identical - although theEDGE is a bit more because of the advanced engineering required to create such a narrow profile. There is also the option of the SF75 bifold door which has a U-Value of 0.9W/m2K which is the lowest of any aluminium system on the market. Given your location and your views, my personal recommendation would be sliding doors, because you maximise your views even when closed - but it is whatever is best for you and it may well be a combination of sliding doors and fixed frames provide the perfect and cost effective solution. If you have any questions do not hesitate to ask and good luck with your project!

I'll start my response by saying we have been supplying and installing award-winning bifold doors and award-winning sliding doors right across the UK for 17 years, so we have plenty of experience - and unlike some others on Houzz we have no bias towards either system. Without seeing the plans it isn't easy to advise completely, but given your comments Rustumshah I think sliding doors are the best option for you. We offer two slim sliding doors, theEDGE which is our award-winning system with ultra-slim 24mm sightlines and Grand Slider II which is our hugely popular slider with 83mm profiles. In terms of choosing between systems, one of the key factors alongside visual appearances is the usability of the doors. If you get the chance to try the doors before you order then I would highly advise it. Historically some of the other systems on the market have been very heavy to open and close so if you can get to one of the exhibitions like Grand Designs Live, Homebuilding & Renovating or Build It Live where you can compare systems then that may assist your decision making. If you want to discuss your particular project where we can answer questions and provide a quote for your project then simply give us a call on 01603 408804, visit or website www.idsystems.co.uk or email us at info@idsystems.co.uk.

I had hardwood bi-folds fitted last year and it took me ages to decide what to get. The reason I finally chose bi-folds was I use all my garden doors several times a day even in the winter and just opening the one section is easy and folds back neatly and doesn’t catch the wind as easily. There also have magnetic catches. And opening three sections is very neat and gives the biggest opening. However these openings are only two metres wide. Where I have a 2.4 opening I’ve got French windows and the 60cm doors fold back and hook onto the side windows well. Tbh bi-folds aren’t my favourite but they best suited the openings.