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Turnkey package versus self project management

There are three options that you can choose, when purchasing a fully insulated room in the garden, all of which have their merits and down sides. They are DIY ASSEMBLY | SELF PROJECT MANAGEMET | TURNKEY SOLUTION. The following examples should hopefully give you an insight as to which is the best way forward for your own personal situation.


1. Self Assemble / DIY Construction

The best way to save money is to buy a garden a shed or a log cabin, add your own insulation & electrics,. Whilst this is a cheaper option, the 'shed' is not suitable for year round use without insulation, electrics, and internal lining. A popular company for this option is Dunster House as it offers a wide range of shapes and sizes, along with the additional insulation and lining packages you need, saving both time and effort spent collecting materials from DIY stores.

The saving on price is likely to have a compromise on quality however, with the building probably built from fast grown timber, it is therefore is likely to be subject to twisting and warping, and in most cases, delivered untreated. This essentially means that you MUST treat the lengths of timbers before they are assembled, which might mean unpacking everything and laying out on the lawn prior to construction. For the best longevity, try and purchase a shell that is constructed using tanalised timber, especially on the floor bearers and the cladding, if you want the building to last.

Assembly of log cabins can be tricky, as the components need to interlock together in a set order, so instructions must be read carefully beforehand. According to Dunster House, you need to allow 4/5 days to erect the building, based on two people installing on site, The other option is to choose a sectional 'shed' that has a panel construction, as this is a much easier way to erect on site. According to Warwick Buildings, their small workrooms can be erected within a day, by two people, leaving another couple of days for the insulation, wiring and lining. 

Once the structure has been erected, you will need to purchase electric cables and do the first fix wiring, which is fairly simple on the sectional building, as the internal frame creates a cavity for the cable to be sited. Log cabins however require additional battens to create a space for the required insulation, so the cables can be sited in that, or simply surface mounted in trunking.

A log cabin is not really suitable for year round use as an office, as the interlocking corners naturally shrink and create gaps for cold air and insects to penetrate through the walls, so pre constructed panels are the preferred choice. This type of construction is also more suited to accommodating the insulation, which needs to be a minimum of 50mm to have any effect. The obvious choices are foil backed Celotex, Rockwool, or Polystyrene (Jablite). The Jablite and Celotex are easy to fit, and offer better sound insulation than the Rockwool equivalent, especially as the Rockwool can slowly drop inside the cavity over time. If you are lining the inside with MDF, OSB, or Plywood, then Jablite s a good option as it stops the cold passing through the external cladding, especially if there is a moisture barrier behind the external cladding. The foil on the Celotex however reflects the heat back into the building so is more efficient especially during the winter. Rockwool is by far the cheapest, but the amount of air in the product provides less resistance to noise and thermo waves, but is still far better than no insulation.

For the best results, ensure you insulate the floor, as this will keep out any cold coming up from a concrete or paving slab base. 

Double glazed doors and windows are also a MUST for working in the garden shed. They can be timber, UPVC or aluminium, however the glass needs to be 28mm thick to provide a good level of insulation and noise protection. Most garden room suppliers are aware of the requirements, and use household doors and windows which also feature up to date security.

This garden office construction will also require a ground supporting (or ground screw) base. In most cases a paving slab base is the way forward, as the DIY enthusiast will find it an easier solution than a concrete pad. Remember, these buildings will be heavier than a small garden shed, so a small plastic square dropped on the grass and filled with a bit of stone, will not be suitable on this occasion. 

Companies in this bracket are Wickes | Dunster House | Warwick Buildings (Workroom range)

Both Wickes and Dunster House solution provide a choice of either log cabins, or sectional summer rooms that can be adapted from a set layout. They are supplied untreated, however that is not likely to be the end of the world for a DIY enthusiast. The Warwick Buildings workroom range offers everything that is needed for this customer bracket, as the sectional construction is pre-built with a double external skin with a vapour barrier. It also includes tanalised cladding and an insulated floor, along with the option of double glazed doors and windows. If you are heading down this route to save both time and money then their Workroom range is certainly worth a look at.

2. Self Project Management

This is the middle ground, and suits a majority of the garden office customers. You can still save you a fortune if you are able to work with a builder and an office supplier at the same time, providing you choosing a manufacturer that will supply and fit modular buildings. The factory built system is the most economical way for the garden room to be built, for two reasons. Firstly - because all the components are on hand to the in house construction team, and the items are bought in bulk, the time and money taken to produce the building is dramatically reduced compared to construction on site - and construction on site is expensive.

Secondly - The designs are usually geared up so that assembly on site is also done extremely efficiently. This even starts with the way the vehicle is unloaded, whereby the components come off the delivery truck and are immediately installed. This again saves on the most expensive component which is the on site labour.  

Whilst a modular design may not always be the most attractive creation, with strategic positioning of doors and windows even a pre-fabricated building can look beautiful if designed cleverly. A useful tip is to experiment with online configurators to design a garden room that looks as if it was constructed on site - it may be that the company can slightly tweak their manufacturing processes and make a world of difference. Good configurators are Warwick Buildings | Green Retreats | Smart Garden Offices

The overall idea however of the modular design is to save money by being efficient. This usually means that external cladding is horizontal and internal lining is either a melamine finish with joining strips, or an unpainted finish with seamless joints. Both are a compromise on a plastered finish - however painting the inside by either yourself or a decorator still saves money compared to a turnkey option. (If a plastered finish is desired, you could ask the modular manufacturers to omit the internal lining, or add your own plasterboard over the top, especially if you know a local plasterer that would do the work afterwards)

Factory built garden rooms usually require a local builder to do the groundwork, which can put off some prospective buyers. This however is understood by the manufacturers, and it is likely that they have good local contractors that will do the job to the required specification. By using a preferred contractor it removes the concern for both the customer and the supplier, as the base usually needs to be done by a professional. Alternatively if you know a local builder, send a picture of the groundwork and the access to the manufacturer, as this will ensure a smooth assembly process.

Remember that these companies want to be as efficient as possible, and will have already allocated time in the schedule to install your building.


Ultimately - managing the project yourself is the most value for money of all the options available, and is easily achieve if you do the following.

Use a recommended base contractor from the garden office company, or employ a trusted base contractor.

Let the garden office company install the building

Use a local electrician for the final fixtures

Paint the interior yourself.

Companies in this range are Warwick Buildings | Smart Garden Offices | Garden Retreat | Crane Garden Buildings


3. Turnkey solution

This option doesn't need much explanation, as it does what it says on the tin.

Firstly you would visit the showroom (if applicable) to view the buildings and finalise your specification.

Secondly, a site visit is required to assess the access and determine where the building will need to be located.

Then you simply wait for the team to install the sub frame, followed by the remainder of the building - which is constructed on site.

The positives for this options is that the manufacturer manages the project for you and deals with any issues that you have on site as you go. This is obviously the best solution if you have no project management experience, are short of time, or have a large enough budget for the initial building (plus contingency for on site alterations during the process.).

The negative side of this option is the cost of inefficiency. Manufacturing on site often takes three times as long as it's in-house equivalent, requires more clearance from boundaries (to fit external cladding) and more room on site for construction purposes. Groundwork is still required - in most cases a pile foundation system is used as opposed to a solid concrete base. This is a cheaper solution and much easier to organise, due to the logistics of skip hire, soil removal and construction materials. Please be aware that a ground screw or a pile foundation doesn't usually have a damp proof membrane so this needs to be factored in, along with a system to stop vermin from nesting under the building. A company that provides a concrete base within the price will usually keep the base at ground level, ensuring that the building is under the permitted 2.5m planning permission height regulation. 


If this option is the best solution for you and the inflated cost outweighs the potential risk of project management the companies in this range are Green Retreats | Oeco Garden Rooms | Eden Garden Rooms | Booths Studios

Creative Garden Rooms 

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