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Dunster House Ltd.
Incorporated. 1994
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Make sure you make the best possible use out of your Log Cabin, whatever the season. Dunster House’s combination of insulation in the wall logs, floor and roofing allow you to keep the temperature in the cabin just right and use it whenever you wish.

You will need to prepare a solid base that is square and level to allow you to build this insulated log cabin successfully on your property. You can use concrete or our RapidGrid Foundation system. We recommend a base of 5.0m x 3.2m for the Severn Warmalog®. The only extras needed are a superior quality light coloured 'Barn' paint to seal the outside of the insulated log cabin, as well as a clear silicone sealer for the joints after decorating. These are available from your local decorator supplies.

Our thermally-insulated Warmalog® cabins are built of special logs - consisting of triple Tongue and Groove logs with a 62mm timber and polyurethane ‘sandwich’, that has better thermal insulation characteristics than competing brands, but at a very reasonable price. Just another new and exciting product, thanks to Dunster House!

As well as the walls of the Warmalog® Cabin, the 50mm floor and 60mm roof provide considerable insulation. The windows are Double-Glazed, with two panes of 4mm toughened glass and a 16mm air gap in a 24mm sealed window unit. These and more thermal design factors give Warmalog® cabins a U value of 0.59. This excellent heat retention makes the Warmalog® the kind of building that will keep you cool in those warmer months while staying warm in the coolest part of the year.

The Warmalog® quality timber building is well-suited to a number of uses, such as an office, work-out room or even your own private bar. So, if you need the extra room for working out or to work or  any other reason, it’s reassuring to know that the changing seasons won’t affect your lifestyle. You can keep on doing what you need to do regardless of the weather! Strong and secure, the Warmalog® has an Espagnolette locking system on its wide-opening French Doors. The roof is held up and strengthened by large Purlin beams, and below your feet, pressure treated floor bearers keep the damp away from the body of the cabin.

The Warmalog® is easy for home owners to assemble. Log Cabins will never be the same again!

Product Features
Insulated Log Cabin Fully Insulated Log
Insulated Log Cabin Fully Insulated Roof And Floor
Fully insulated

We never compromise on quality which is why the insulation that we use in our Warmalog cabins is of the highest specification. It’s called polyurethane and it is one of the best insulators available, it’s so effective that even NASA has used it to insulate the external fuel tanks of their space shuttles!


Polyurethane is a great material because not only is it lightweight and versatile, its high thermal conductivity makes it sought after. Competitors insulation might be cheaper, but they may use Rockwool or polystyrene, which are inferior materials. Polyurethane is said to be 50% more efficient than Polystyrene and up to 100% more efficient that Rockwool.


It’s not just the walls that are insulated in a Warmalog cabin! We also provide the same kind of insulation for the roof (60mm thick) and for the floor (50mm thick). As well as this coverage, the Warmalog cabin comes with 24mm thick double glazing as standard.


All of this heat-retaining technology ensures that any Warmalog cabin can achieve a U-value of 0.59. The U-value assesses the rate of heat loss / gain through all the thicknesses of the combined elements that make up a building component such as a wall, floor or roof. Simply put the higher the U-Value the worse the product performs. Our Warmalogs U-Value of 0.59 is considered to be very low, meaning you’ll save a fortune on heating bills compared to Polystyrene or Rockwool insulated cabins!


Wide Opening Windows Warmalogs
Wide Opening Windows
Our garden log cabins feature key-lockable outward opening windows, so you don’t lose internal space, allowing you to accommodate furniture underneath the window. Our windows have been designed to include draft seals that prevent wind and rain from entering your garden retreat. You may think it’s over the top, we think it’s just standard.
Multipoint Locking Windows Warmalogs
Multipoint Locking Windows
Just like our doors, we use mushroom headed espagnolettes which pull the window tightly into the draft seals attached to the frame. We also supply a solid handle and key that allows you to lock the window whilst you’re away. We also supply Georgian Bars as standard. Most log cabin companies only supply a multi-purpose stay arm opener for both locking and keeping the window open.
Internally Beaded Windows Warmalogs
Internally Beaded Windows
Both our doors and windows are fitted with internal beading used to secure the glazing in place. This beading style is typically found in uPVC windows and is a proven method of security. However, there are still some companies that externally bead their windows. Allowing intruders to remove the glazing from the outside of your garden house and gain access.
62mm Interlocking Logs Warmalogs
62mm Interlocking Logs
We only use full lengths of engineered precision cut and routed tongue and groove timber in our log cabins. These logs go through a process of being planed, leaving you with a smooth finish. We believe that using full lengths of planed timber gives you a more aesthetically pleasing and stronger product.

Other companies are happy to provide you with rough offcuts, glued and finger jointed together, creating a weakened cabin and off-putting appearance.

Severn Insulated Log Cabin Avoid Planning Permission
Avoid planning permission
Our Severn Warmalog is less than 2.5m high and therefore exempt from UK planning conditions and permitted development, even if it is close to the boundary of the property. This frees you from legal restrictions and allows you more freedom to choose your ideal site. You can now consider more personal factors such as the amount of direct sunlight it’ll receive, how easy it is to access and its aesthetic appeal.  If you want to find out more about permitted development rights see our planning guide
Insulated Log Cabin Toughened Glass
Insulated Log Cabin Styrene
Toughened glass

The 4mm toughened glass that’s used to make up the double glazing in our windows and doors of our Warmalog cabins for increased security and resilience. It's much better than the 3mm ‘Shed-Spec’ horticultural glass which is commonly found in our competitors garden buildings.  It is much more difficult to scratch or bend than the plastic alternatives, such as Styrene, Acrylic and Perspex, so it'll preserve the clear view of your garden.


The tempering process makes our toughened glass far stronger than the alternatives, and harder to break than normal glass. In addition, if it does happen to break, it will shatter into many small pieces, rather than scattering dangerous, razor-sharp shards. So confident on the superior quality we tested it against the other types of glass commonly found on the market and, of course, it came out on top!


Insulated Log Cabin 24 mm Double Glazing
24mm double glazing

This Warmalog cabin comes complete with 24mm sealed window units for increased insulation and noise-reduction. This is a single, ready-to-install unit comprising of two sheets of 4mm toughened glass with a 16mm aluminium spacer, which allows for optimum convection current between the glass, ensuring condensation-free windows.


They are made in our own factory and fully conform to European Standard EN1279, unlike most of our competitors. 


Insulated Log Cabin Slow-Grown Spruce Wall
Insulated Log Cabin Slow-Grown Spruce Timber
Slow Grown Spruce, Not Cheap Pine

Unlike our competitors, we only use high-quality spruce timber in our garden log cabins rather than cheap pine or mixed timber. Why do we use slow grown spruce rather than the much cheaper knotty pine alternatives?


Spruce is considered more stable as it expands and contracts less than pine. This stability means that the spruce walls of our garden buildings minimise gaps appearing as the timber changes along with the weather.  We responsibly source all our timber, where it grows slowly in the cold northern regions. We all know the old adage of counting the rings to see how old a tree is, well our timber grows slower, and takes longer to get to size meaning it has more rings in it. This means it has a tighter grain, and each ring helps prevent cracks and shakes appearing in the densely packed timber.


Our garden buildings really are built to last therefore we use only the highest quality, slow-grown spruce.  Spruce is much more resilient to warps and splits compared to its cheaper alternative pine. Being a whitewood, it doesn’t discolour anywhere near as much as pine so it is also much more aesthetically pleasing for a log cabin. Considered more stable, less knotty and resinous than pine, spruce will also produce a lot less sap. It is also less dense meaning it is not as susceptible to mould and rot.


Many manufacturers use a mix of timber saving them money. They will buy the lowest cost timber and then mix these up during production, often using finger joints. Ending up with a cabin, where the walls are a mix of pine (redwood) and spruce (whitewood). Not only does the log cabin then look comical, with stripy walls of different timbers, but this just shows a lack of pride about the finished product. 


Severn Insulated Log Cabin Pressure Treated Bearers
Pressure treated bearers
The Severn Warmalog features pressure treated floor bearers. These are the parts of the cabin most at risk from damp conditions, so it's essential that they are well-protected! A high-pressure chamber is used to drive protective chemicals deep into the pre-cut lengths of timber, providing pre-prepared long-lasting protection. We guarantee that the pressure treated timber will remain free from rot and insect infestation for up to 10 years!
Insulated Log Cabin 10 Year Guarantee
Insulated Log Cabin 10 Year Guarantee II
10 year guarantee
All of our Pressure Treated Timber comes with a genuine 10-year Guarantee against rot and insect infestation. The process of pressure treatment forces the wood preservative into the timber rather than simply dip treating (essentially just covering the exterior) like many companies still do. If the timber is only dip treated then you would have to buy and apply treatment to your cabin every single year in order to maintain their worthless 'guarantee'. 
Severn Insulated Log Cabin Tall Walk-through Height
Tall walkthrough height
The Severn Warmalog extra tall doors have a walkthrough height of 1.88m (6’2’’) to allow you to move awkward objects or furniture in and out of your new cabin with ease, welcome in more light, and to minimise the chance of bumping your head.
Severn Insulated Log Cabin Avoid Sagging Roof
Heavy Duty Roof Purlins
Purlins are the large timbers used for structural support in buildings. We use very thick, heavy-duty roof purlins to support your cabin.  At 140mm x 45mm they are amongst the thickest purlins available on the UK market. Competitors will often use thinner purlins to keep their costs down which means their roofs will not be as strong as ours. Using thinner purlins risks the roof collapsing or sagging during extreme weather – and that’s the last thing anyone wants!
Insulated Log Cabin 4-Point Locking System
4-point locking system
Windows and doors are at the heart of your Wamalog’s security, and we design ours to ensure that only welcome visitors can enter your building. We feature as standard, a secure four-point locking system, including: hook, locking latch and two roller cams. We combine this with a 6 pin Euro cylinder, the same type of lock cylinder you would find on the front door of a typical house. Why should your log cabin be any less secure than your home?
Severn Insulated Log Cabin Adjustable Hinges And Friction Stays
Adjustable Hinges and friction stays

Our expertly joined windows come with stainless steel friction stays, typically found on the uPVC windows in your home. This eliminates the needs for the typically found stay arm openers, commonly used on log cabins.


We’ve all, at some point in our lives, left the window open and it suddenly starts to rain. Usually, this would be an issue for normal window hinges. However, there’s no need to panic about rusty hinges with our domestic stainless-steel hinges.


We also include heavy duty easy-adjust hinges for our doors which allow you to make minor changes if ever required. 
Insulated Log Cabin Storm Braces
Storm braces
To control natural expansion and contraction in the timber, the Warmalog features steel straps on the inside and outside of the cabin known as storm braces, Secured by screws and bolts, these braces are adjusted to spread the timber's natural movement equally across a much larger area, thus avoiding the worst effects of localised expansion and contraction within the wood. 
What is a Warmalog Insulated Log Cabin?
A: A Warmalog® Insulated Log Cabin is a garden building unique to the Log Cabin industry and exclusive to Dunster House. This unique Log Cabin features a 62mm sandwich of slow-grown Spruce timber and Polyurethane insulation, which come together to create a revolutionary type of wall log. and roof and floor insulation, this creates a thermally efficient garden building perfect for using all year round. Warmalog® Cabins are insulated in all directions. The floor has a 50mm thick insulated structure, the roof is 60mm (also insulated), coupled with 24mm double glazed sealed units made from 4mm toughened glass. Thanks to these and other heat-conscious design details, these Warmalog® cabins have an equivalent U value to 110mm logs and achieve a U value of 0.59. This means that you can feel confident your cabin will remain cool in the warm months and warm in the cool months.
What size cabin can I have?
A: We offer a range of Warmalog cabins. The smallest is 2.8 metres wide by 3.0m deep, and the largest is 4.8m wide by 5.8m deep.
How big is this Insulated Log Cabin?
A: This Insulated Log Cabin’s measurements are: 4.79m (15' 8") x 2.99m (9' 9")
How high is this Insulated Log Cabin?
A: It is 2.49m (8' 2") high
How much is this Insulated Log Cabin?
A: This product starts from £5,299.99
What base do I need for this Insulated Log Cabin?
A: We recommend a flat, level base at least 100mm bigger on each side. e.g. A 4m by 3m building would have a base of 4.2m by 3.2m See more details here. The base can be concrete or made from our RapidGrid Foundation system.
Can I paint the Log Cabin?
A: Yes we recommend a superior quality light coloured 'Barn' paint for the exterior, as well as a clear silicone sealer for the joints. These are available from your local decorator supplies.
Where can I visit you? Do you have a store near me?
A: We have 6 branches across the UK. Click here to find the nearest one! Please check with us before you visit if you are travelling to see a particular product.
Do I need planning permission for this Insulated Log Cabin?
A: Take our quick survey to find out!
How thick are the walls?
A: The walls of this Warmalog Insulated Log Cabin are 62mm Thick.
What are u-values?
A: U-values tell us about the heat loss properties of the material you are measuring. The lower the number, the better insulated the Log Cabin will be. Find out more here.

We deliver our products to mainland United Kingdom (England, Wales and Scotland). Some exceptions apply; these are illustrated on the map below.

Scottish areas may be subjected to slightly longer delivery turnarounds, please contact us for details. FREE delivery on selected products over £200 to mainland England and Wales.

Delivery to postcode areas PL, TQ, TR, EX may take 1 week longer, beyond the delivery shown on the product page.

Delivery Price

Green - £19.99 delivery fee on all orders under £200.

Blue - Delivery to postcode areas PL, TQ, TR, EX6, EX7, EX20, EX21, EX22, EX23, EX39 may take 1 week longer, beyond the delivery shown on the product page.

Yellow - £59.99 delivery fee.

Orange - £84.99 delivery fee.

Red - We are unable to deliver to these areas.

Assisted Delivery

If you cannot provide an able bodied person to offload the vehicle with the help of our driver, we can provide additional manpower with our Assisted Delivery Service. The driver will arrive with some help to unload the lorry, meaning that you can put your feet up.

We offer this service on all items that are delivered, we do not offer this on our couriered products. Prices for this service can be found on individual products.

Should you require further information on our standard or assisted delivery services, please contact a member of our Sales Team.

Scottish areas may be subjected to slightly longer delivery turnarounds, please contact us for details.

Warmalog temperature test - 19/04/2017
Temperature outside the Warmalog Cabin:  11°c
Temperature inside the Warmalog Cabin: 12°c

Temperature after using a 2KW heater:
After 30 minutes: 22° c
After 60 minutes: 30° c

Wall, roof and floor temperature:
The top of the rear wall: 35°c
The bottom of the rear wall: 30°c
The top of the window wall: 32°c
The bottom of the window wall: 30°c
The top of the door wall: 34°c
The bottom of the door wall: 29°c
The top of the full wall: 35°c
The bottom of the full wall: 32°c
The temperature of the roof averaged between 34°c and 35°c
The temperature of the floor averaged between 28°c and 29°c

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