Log Cabin Workshop 3.5m x 4.5m

[BCS1980UK]

Greetings,

Today we started the works for my (small) home workshop. The house that we bought 2 years ago had a two-car driveway. We only have one car and no intention/need to have another so the extra parking was only being used when my in-laws come visiting (no more than twice a year).

The workshop itself will be a 4.5m x 3.5m log cabin (Dunster House Lantera), 45mm walls, floor and roof insulated. It is intended for hobby on weekends, not for work.

Today the outside wall and broken fence came down, new fence and new drainage were installed. Tomorrow (weather allowing) the concrete base will be poured. Then, other landscaping work will be carried on whilst I wait for Dunster House to deliver the kit.

 

[disco_monkey79]

Looks much smarter already! Keep the updates coming

 

[BCS1980UK]

Looks much smarter already! Keep the updates coming

Thanks. Will do.

 

[Sachakins]

Are you planning on compacting that rubble before you lay shuttering, DPM, Insulation then concrete pour?

 

[Yojevol]

Are you intending to treat the timber before election? Over time the timber will dry out, move and split. The corner joints, especially, become vulnerable to water ingress and rot can set in unseen, so pressure treatment before assembly is worthwhile.
After assembly I would recommend a surface sealant which could be a paint finish but it will need regular maintenance so will you have sufficient access all around the shop?
Do Dunster House have recommendations on base design? It is important to design out any possibility of water ingress at base level.
Here speaks somebody who has lived with one of these structures for the last 16 years.
Brian

 

[redhunter350]

I agree with Yojevol ---Not sure where your property boundaries are but I would have tried to ensure there was sufficient space all around the building for future maintenance -- wood treatment etc etc.
Also ensure the wooden bearers have a DPC under them.

 

[BCS1980UK]

Thank you all for your replies and recommendations.
@Sachakins under that pile of rubble (that needs to be cleaned out) is the original concrete driveway. The new concrete pour is to elevate it (around 50mm) and, most importantly, level it. On top of it will go the 50mm pressure treated bearers with 25mm PIR insulation panels (suspended) between them, and the 19mm floor on top (as per illustration).

@Yojevol and @redhunter350 the bearers are pressure treated. The base design is the one recommended by Dunster House. They must be tired of my technical questions by now. For the walls paint/protection my plan is to use Cuprinol Garden Shades (any other recommendations/suggestions?). I made sure that I can remove the fence panels all around to access for maintenance. To one side the fence is to my own driveway, to the back it is to the council's substation (I have access to it), and to the other side my neighbors gave me full access to raise the fence. Just in case in the future they move out and the new neighbors are not nice, I made sure that I can squeeze in on that side. Tight but doable.

Thank you all for your recommendations

Edit: In time, the work is being done by qualified contractors and the design/specs were reviewed by a work colleague.

 

[Yojevol]

Thank you all for your replies and recommendations.
@Sachakins under that pile of rubble (that needs to be cleaned out) is the original concrete driveway. The new concrete pour is to elevate it (around 50mm) and, most importantly, level it. On top of it will go the 50mm pressure treated bearers with 25mm PIR insulation panels (suspended) between them, and the 19mm floor on top (as per illustration).
View attachment 179185

@Yojevol and @redhunter350 the bearers are pressure treated. The base design is the one recommended by Dunster House. They must be tired of my technical questions by now. For the walls paint/protection my plan is to use Cuprinol Garden Shades (any other recommendations/suggestions?). I made sure that I can remove the fence panels all around to access for maintenance. To one side the fence is to my own driveway, to the back it is to the council's substation (I have access to it), and to the other side my neighbors gave me full access to raise the fence. Just in case in the future they move out and the new neighbors are not nice, I made sure that I can squeeze in on that side. Tight but doable.

Thank you all for your recommendations

Edit: In time, the work is being done by qualified contractors and the design/specs were reviewed by a work colleague.

If not pressure treatment at least slosh a load of preservative in and around the joints as it is erected.
Brian

 

[BCS1980UK]

If not pressure treatment at least slosh a load of preservative in and around the joints as it is erected.
Brian

That's a good idea. Thanks.

 

[Jester129]

Green with envy.

 

[BCS1980UK]

I have contacted Cuprinol technical team and they confirmed that their wood preserver and their Garden Shades line are compatible, so thanks @Yojevol for the suggestion. I asked if I could apply the preserver profusely on the individual pieces a couple of days before assembling and they replied it is fine.

The base is now done.
Next step is to receive the kit from Dunster House.

 

[Sachakins]

Nicely done base.
Do you think filling in that open triangle in the corner with concrete would prevent a water trap point?

 

[Setch]

When I erected my Dunster cabin I had a paint kettle of clear wood preserver on hand, and each timber got a generous application along the grooved joint surfaces as it was assembled. Once it was completed I used a garden sprayer to treat the inside, and painted the outside with a dark preservative supplied by Dunster house.

Ten years on it's in very good condition, though it is overdue for as fresh coat of preservative on the outside. My biggest regret is following Dunsters instructions on the concrete base, which was significantly oversize, and generates quite a lot of rain splash up the walls. I wish I'd been able to make it 10mm smaller than the cabin so the timbers overhung by 5mm on all edges, I think this would have reduced the tendency for water to get under the bearers in heavy rain. I suspect Dunster are worried people will build the base too small, so they err on the side of too big with the dimensions provided.

 

[BCS1980UK]

Nicely done base.
Do you think filling in that open triangle in the corner with concrete would prevent a water trap point?

Hi @Sachakins
There is a rainwater drain on that "triangle". Was the original drain of the driveway.

 

[BCS1980UK]

When I erected my Dunster cabin I had a paint kettle of clear wood preserver on hand, and each timber got a generous application along the grooved joint surfaces as it was assembled. Once it was completed I used a garden sprayer to treat the inside, and painted the outside with a dark preservative supplied by Dunster house.

Ten years on it's in very good condition, though it is overdue for as fresh coat of preservative on the outside. My biggest regret is following Dunsters instructions on the concrete base, which was significantly oversize, and generates quite a lot of rain splash up the walls. I wish I'd been able to make it 10mm smaller than the cabin so the timbers overhung by 5mm on all edges, I think this would have reduced the tendency for water to get under the bearers in heavy rain. I suspect Dunster are worried people will build the base too small, so they err on the side of too big with the dimensions provided.

Thanks for sharing, @Setch
That's good to know. I have (very) little play to position the cabin on the base. Do you think I should try to align flush or overhang 5mm on a corner (front and one side, for example) to reduce splashing on at least 50% of the edges?

 

[SimonB]

Does this fall within the "substantially non-combustible material" requirement of Building Regs and if so have you addressed this with your local authority, given the boundary proximity? If not then perhaps worth doing so now, before erection, rather than being made to take it down after.

 

[Setch]

Thanks for sharing, @Setch
That's good to know. I have (very) little play to position the cabin on the base. Do you think I should try to align flush or overhang 5mm on a corner (front and one side, for example) to reduce splashing on at least 50% of the edges?

I opted to position mine so the bearers were essentially flush with the back and side nearest my neighbour. The step this created at the front is mostly sheltered by the overhang above the double doors, and is quite nice to sit on in good weather.

I also assembled mine differently to the supplied instructions, so that the pedestrian door and double doors are at the same end of the workshop. This made more sense given the layout of my garden, and doesn't seem to have adversely effected the structure.

I'd also suggest fitting the storm braces as soon as possible - I left mine off, and went away for the weekend after errecting the shed. Unsurprisingly, there was an epic storm that weekend, and I had to call my parents and implore them to go round and secure the roof before it ended up in orbit!

 

[BCS1980UK]

Does this fall within the "substantially non-combustible material" requirement of Building Regs and if so have you addressed this with your local authority, given the boundary proximity? If not then perhaps worth doing so now, before erection, rather than being made to take it down after.

Hi @SimonB
It falls under the permitted development rules. Theoretically I didn't need but I applied for a certificate of lawful development anyway. I added the location plans and the technical specs sheet from Duster House. It took 2 months but I received the Council's approval without any restriction or comments.

 

[BCS1980UK]

I opted to position mine so the bearers were essentially flush with the back and side nearest my neighbour. The step this created at the front is mostly sheltered by the overhang above the double doors, and is quite nice to sit on in good weather.

I also assembled mine differently to the supplied instructions, so that the pedestrian door and double doors are at the same end of the workshop. This made more sense given the layout of my garden, and doesn't seem to have adversely effected the structure.

I'd also suggest fitting the storm braces as soon as possible - I left mine off, and went away for the weekend after errecting the shed. Unsurprisingly, there was an epic storm that weekend, and I had to call my parents and implore them to go round and secure the roof before it ended up in orbit!

Oh... wind around here is crazy. I am afraid I will wake up in Oz one day.
Did you fit the storm bracers inside or outside?

 

[BCS1980UK]

I just had the first hiccup of the project.

Dunster House advertises that the delivery is between 1 and 15 working days, which in my case would be up to the 26th of April. Today they set the delivery date to the 9th of May which In my opinion is unacceptable (50% delay of schedule). I have the contractors on standby to finish the garden works after the cabin is built, so right now my garden is not usable and I had already invited friends over for the 6th May bank holiday.

I have just formalized a complaint. Let's see what will be the answer.