Andy H

I attended a windows webinar today run by NSBRC. Apparently the calculation of U-Values is to be done in accordance with BS EN 410: 2011

At the moment its windows. I'm getting quite a different range of values for triple glazed windows from a range of different companies. I'm going to be building using ICF and the U-Values are very similar between suppliers for the same thickness of EPS so I feel confident with ICF block U-Value quotes. In the case of the windows I am less confident - do they have to get certification from an independent 3rd party and are there specific factors that contribute to a lower U-Value that I can see if they are features of the lower U-Value windows to get comfort? Andy

Is there a way to verify or get some reassurance about U-Values quoted by suppliers? Thanks Andy

I have been thorough on reading the legislation re permited development but have not gone for written approval from the council because of the need for plans! I will need a structural engineer as my Building Regulations inspector expects them. What does the abbreviation 'BW' mean? Thanks Andy

I am building a single storey building in my garden 6m by 12m by 3.25m heigh. It will sit on an insulated slab (e.g. Isoquick or Kore) with the walls being ICF. Apart from a small toilet/shower room and a small room/ large cupboard for utilities the building will essentially be one large room. The building is being done under permitted development rights so there is no need to submit plans to the planners. I am planning on constructing the building myself with a friend and calling upon external help where needed, this will be my first building project. I would like to avoid any unnecessary expenditure and think that may include architect fees. My thought is that the Architect drawings largely serve the purpose of communicating to the builder how the building is to be constructed but as I will be the builder I will already know how I intend to build. I am currently at the design and budgeting stage although I have done some excavation for foundations and have been able to get quotes from suppliers so far without architect drawings. The one area I am anticipating may be an handicap without an Architect is getting a Structural Engineers calculations. Are there benefits from using an Architect that I am not factoring in or other reasons why I will need to bite the bullet and pay for an architect? Thanks for any feedback

I can see the ease of adding insulation onto the inside of the building but the ICF suppliers seem to reduce the U value by increasing the thickness of the outside of the block. There presumably is a reason for doing this. Is anybody able to explain this?

Thanks Joe90 and TonyT

I am building a single storey building under permitted development rights and am subject to a maximum build height of 2.5m. In order to get a good ceiling height I am digging below ground. The less space I can take up in the roof construction the less I need to dig out. I would like to get a U value of 0.15 or better and am happy to have any structural beams that may be required to remain exposed rather than loose space by covering them up with plaster board, providing it meets fire regulations. The building is to be an ICF construction, 12m by 6m and will not have any internal walls to provide structural support. I currently have 2 ideas: 1 an insulated floor panel called 'themafloor' by Thermohouse which is like an insulated form that can span the 6m onto which a 100mm concrete with rebars is poured - this would give a depth of 32cm but would need a small amount of additional insulation to get to a U of 0.15 along with a waterproof topping. 2 Cold pressed steel beams that span the 6m to which are attached an insulated roof panel from somebody like Kingspan. I am assuming that the cold pressed steel beams could be left exposed but I may be wrong. Any thoughts on these options and any other ideas would be appreciated.

I am building a single storey building under permitted development rights and am subject to a maximum build height of 2.5m. In order to get a good ceiling height I am digging below ground. The less space I can take up in the roof construction the less I need to dig out. I would like to get a U value of 0.15 or better and am happy to have any structural beams that may be required to remain exposed rather than loose space by covering them up with plaster board, providing it meets fire regulations. The building is to be an ICF construction, 12m by 6m and will not have any internal walls to provide structural support. I currently have 2 ideas: 1 an insulated floor panel called 'themafloor' by Thermohouse which is like an insulated form that can span the 6m onto which a 100mm concrete with rebars is poured - this would give a depth of 32cm but would need a small amount of additional insulation to get to a U of 0.15 along with a waterproof topping. 2 Cold pressed steel beams that span the 6m to which are attached an insulated roof panel from somebody like Kingspan. I am assuming that the cold pressed steel beams could be left exposed but I may be wrong. Any thoughts on these options and any other ideas would be appreciated.

Planning was an option but I wouldnt have wanted to go much above 2.5m above the garden level as the building would be too dominating in the garden.

Having thought I had decided on Isoquick I have come across many recomendations for Kore so I have asked for a quote from Kore.

The building is not going to be occupied in the sense that somebody will be living their. The 'kitchen'' will be a sink, kettle and microwave. Its likely to be in use 1-2 hours per day. In view of this do you think it is something I still need to be concerned about? I will do a little research myself as this is something I have never heared off - thanks for bringing it to my attention.

It depends on the foundation specifcation but if I assume that the hardcore(20cm) insulation(20cm) and concetere slab(20cm) take up 0.6m and the roof takes up a minimum of 0.3m then to get an internal height of 3.25 metres and stay within permitted development rights of 2.5m I would require a depth of 1.65m. I am currently at 1.25m

I am planning on building a single storey building 12m by 6m by 3.25m (approx 0.7m underground) at the bottom of my garden in London. Whilst the building will be South facing it will receive very little direct sunlight in the winter as the sun will be obscured by the House and other houses on the Street. The North, East and West facing walls receieve minimal light due to neighbouring properties or fencing and will therefore not have any windows. Whilst I woud want a very low U value for the winter months my concern is that could lead to overheating in the Summer. Am I right to be concerned or can this be dealt with by the MVHR unit, install awnings that can be rolled out in the summer to shade the windows and opening the windows over night. In escence should I still be aiming for a low U value. Connected to this is the question as to whether there would be any benefit in removing the inner eps of the ICF to allow for the concrete wall to help with temperature regulation. As an aside I quite like the idea of have a concrete wall as the wall finish. Thanks Andy

In the summer of 2020, having no building or home improvement experience to my name I decided to do some home improvements. With a friends son I put in some new garden fencing, repointed the stone driveway and refurbished the woodwork of the garden bench and table. Emboldend by these accomplishments I felt ready for a much bigger challenge; the construction of a building at the bottom of the garden to provide me with a workshop, gymnasium and bike storage facility. This to be done with my own hands and those of my friends son! There were 3 obstacles in the way - 2 trees and my lack of knowledge / experience. One of the trees was a large Bay leaf tree, located where I wanted to build and the other a more substantial Ash tree located next to where the building foundations would be. to be continued!

I am new to self building and stumbled across your forum. I have spent a few days browsing various topics and am impressed by the quality of the advice, information and the kind manner in which it is given. Being new to self building at this stage I'm unlikely initially to be able to offer much advice to others but as my knowledge and experience grows I look forward to being able to contribute to others. I have chosen to start a blog ("Garden Escape") that records the journey of my first self build; a single storey building at the bottom of our garden that is intended to fulfill a number of functions - home gym, workshop, bicycle store and bolt hole - located in London I am completing the build under permitted development and in order to get an internal ceiling height in the range of 3 to 3.25m I am excavating to allow the building to start underground. This introduces additional complications and along with the building being close to the 3 neighbouring boundaries this seems quite a challenging project to undertake. I have plenty of time available to work on the project and along with a friends son I am aiming to minimise the amount of involvement of others to keep build cost down. I do recognise that I will need to pay for some skilled help and through this forum I will look for guidance on when that may be the case. The project started in the summer of 2020 by the removal of 2 trees and the excavation of a hole 12.5m by 6.5m by 1.2m deep, which is now shuttered up with plywood ready to restart in Spring 2021. I have appointed a Building Regulations inspector and had an initial site visit from a structural engineer (not yet appointed). The decisions I have so far made are: 1. Build using ICF either Isotex or Logix 2. Foundation to be Isoquick raft 3. Build in the principles of Passive housing but am not looking for cerification. 4. To build as close as practically possible to the neighbouring boundaries to maximise the building space. 5. The building is to include a toilet, shower and small kitchen facilities - mains drains approximately 40 meters away at the front of the house. I have done alot of reading up online in the last month and on this forum in the last couple of days but as you might expect I have a ton of questions. For now I would like feed back on the best way to get advice through the site. Should I post seperate questions into specific forums, put the queries through the blog, an initial post with all my current queries or message individual members whom appear experienced with the specific queries? Kind regards Andy