Revised timber frame details with stone cill

[maxdavie]

I posted a few days ago with a timber frame 'cassette' system sunken below ground. It was met with skepticism (or outright disbelief) and I got lots of useful feedback. So, I changed the detail. 

 

I'm now sharing my updated details for the purposes of: 

 

1. comment if there is any

2. sharing for sharing's sake (I'm new to this community so not sure if it's strictly problems-that-need-solutions content only or you're all just a bunch of self-build nerds that enjoy looking at construction details and other's progress. Please do tell me if this is a pointless post...) 

 

Anyway here are the updated details and a screenshot from my Enscape environment so you can see the visual intention of the details. 

[CharlieKLP]

What is your external timber column made out of? Currently you usually need to use steel if it’s supporting  any structure. I think this is a  building warranty issue… so it makes it difficult to get mortgage and resell. Would that be an issue for you?
 

I don’t think the timber will support a cantilever either as an option. I’m sorry this might be a bit of a bummer. 

[maxdavie]

The external timber is all Larch. 
The large cantilever is achieved with a double joisted beam within the cassette. Engineer’s design. 
The post only has to hold itself up - it’s part of a trellis (not fully shown in that image). 
What sort of warranty are you talking about? 
I haven’t looked into warranties for this, but an LABC New Homes Warranty is on my radar for the next project - which will be a new home.  
 

[CharlieKLP]

I think you will be ok if it’s just trellis.

 

I’d be happier using a steel portal frame, but if timber is ok then it’s likely ok!

 

I think it looks really nice btw.

[maxdavie]

Thanks Charlie! 
Fingers crossed it all comes together okay on site 

[Russell griffiths]

What are your thoughts on services. 
where are you running your pipes and cables. 
 

if you go down this route it would be more suitable to be built on an insulated raft, which will remove a lot of cold bridges. 

[maxdavie]

7 minutes ago, Russell griffiths said:

where are you running your pipes and cables.

There are no wet services in this garden room. Heating is all electric. 
I have an 18mm service void behind the plasterboard for cables - which I hope will be wide enough. 
I’ll increase that for future projects for pipe work. 
 

 

[Gus Potter]

6 hours ago, maxdavie said:

I posted a few days ago with a timber frame 'cassette' system sunken below ground. It was met with skepticism (or outright disbelief) and I got lots of useful feedback. So, I changed the detail. 

 

 

That's the great thing about BH that I appreciate.  Henry Ford et al the car maker alluded to this. Best way to learn is from others mistakes and not repeat in the hope that it will be ok on the day.

 

For me the details look expensive to build, hard to supervise and even if doing it all yourself when you get to the door openings the forming of this it will be really difficult, time consuming, frustrating and at the end of the day you may cut corners.

 

In this current climate it's not easy to buy anything that is not bog standard.

 

I would have a serious think about how this complex detail is going to cost you. Think about a trade off. Maybe accept that in the round the base detail may not be perfect in terms of energy loss in isolation. Make a saving here by going for a standard detail then use this saving to deliver more benfit else where?

 

If you are concerned about the environment in the long term then we should be designing things that will last for 100 years at least and can easily be maintained. We should have a mind to others that come after us.. we have a duty to design such that things can be adapted at reasonable cost for later generations? Ask yourself what is it you are trying to achieve?

 

 

 

 

 

 

[saveasteading]

1 hour ago, Gus Potter said:

we should be designing things that will last for 100 years at least

Exactly.  Experimenting is fine, but risky. 

Design for the weather conditions and a building can last indefinitely. 

 

Look at The Burrell Collection  in Glasgow, reopened this week. 

 

Opened 1983

Closed because of leaks 2016  (33 years before leaking and being shut isn't great, but it was leaking long before that.)

Reopened 2022 after works costing £69M

 

A building is here to keep us or our property out of the weather, with looking pretty and letting light in coming second.

 

The original designers (whose roof leaked) have criticised the revised designs.

Interesting I think, as to what we expect of Architects. https://www.architectsjournal.co.uk/news/opinion/glasgow-is-butchering-the-burrell

 

BUT the collection and gallery are rather good, and I recommend a visit.

 

 

 

 

[saveasteading]

8 hours ago, maxdavie said:

comment if there is any

I being a Philistine, would simplify this massively.

The raft foundation seems excessive unless the ground is very poor.

The edges will  require skilled shuttering joiners, but they won't be much interested in  a  small job.

Never did understand why we should put sub-base in the bottom of a trench.  Lean-mix concrete for me.

The step is a brick sitting on the geound..it will move un less supported by the building.

Cold bridge at the sole plate.

dpm on the outer face of the raft will be torn/crumpled during construction. You shouldn't need it if the concrete is dense enough.

[SteamyTea]

On 30/03/2022 at 17:31, maxdavie said:

2. sharing for sharing's sake (I'm new to this community so not sure if it's strictly problems-that-need-solutions content only or you're all just a bunch of self-build nerds that enjoy looking at construction details and other's progress.

We are all that, and like to smirk at others when things go wrong.

 

Back to your original idea, and maybe others can comment, how about sheathing any timber that is going to get wet often, or is partially buried, in GRP.

Done properly, it will easily last 60 years.  Done badly, a couple of weeks.

Foamglass can be used to thermal structural elements as well, but not had any experience of it.

[Iceverge]

Hi @maxdavie,

 

Nice looking artistic render.

 

Keep the questions coming. If we never explored different ways of doing things we'd never learn. 

 

 

I have a couple of queries about the section provided. 

 

1.What supports the external block and stone sill?
 

2.I think the cladding could get very grubby/decay being in the rain splash zone, although the aesthetic is nice. 

 

3.Again with the DG unit, water pooling may cause a decay/ingress issue. 

 

 

 

 

 

[maxdavie]

On 31/03/2022 at 00:12, Gus Potter said:

Ask yourself what is it you are trying to achieve?

 

On 31/03/2022 at 01:54, saveasteading said:

Interesting I think, as to what we expect of Architects.

 

These are some pretty existential questions about the profession! I know of course first and foremost a building must be built to last - especially in a time of climate crisis. 

But, I do think looks matter. I think some eco-builds can lack character and look a bit stark. A lot of the time people pull down ugly buildings. So in this sense, attractiveness can contribute to the longevity of a building.

My aim - over the course of my career - will be to try and design and deliver attractive buildings that are good for the planet. But, there are bound to be some trade offs where I'll have to weigh up one goal against another. 

 

12 hours ago, SteamyTea said:

We are all that, and like to smirk at others when things go wrong.

Ha! I'm in gd company then! 

 

7 hours ago, Iceverge said:

I have a couple of queries about the section provided. 

 

1.What supports the external block and stone sill?
 

2.I think the cladding could get very grubby/decay being in the rain splash zone, although the aesthetic is nice. 

 

3.Again with the DG unit, water pooling may cause a decay/ingress issue. 

 

1. After Saveasteading pointed out the blockwork would sink, I've introduced a steel bracket that I think we can bolt back into the slab - the block can partially bear onto this. - See revised detail. 

2. Maybe if I can reduce the depth of the stone a bit so there is no protruding ledge it will help......need to think this one over

3. The glass installers think an EDPM membrane should work as second line of defence in case of water ingress 

[Iceverge]

I would argue that utility and economy trump aesthetics for longevity. 

 

Stålekleivloftet storehouse in Norway, about 900 years old, in an area that gets about a meter of rainfall per year. 

 

 

 

A narrow pallet of proven materials, utmost respect for the weather, especially the rain, it keeps most of the water off and the rest can dry quickly.

 

Plain shape and form, accurately constructed. Not burdensome to construct or maintain. 

 

I reckon it'll see 1000 years. 

 

 

 

 

 

[CharlieKLP]

1 hour ago, maxdavie said:

 

1. After Saveasteading pointed out the blockwork would sink, I've introduced a steel bracket that I think we can bolt back into the slab - the block can partially bear onto this. - See revised detail. 

2. Maybe if I can reduce the depth of the stone a bit so there is no protruding ledge it will help......need to think this one over

That’s super weird. I think there’s a reason we leave technical details to technicians! 
I do applaud you having a go, and I’m guessing you don’t need building regs because it’s permitted development, but I’d use standard details if I was doing this. 
 

 

Re architecture… A building doesn’t last 1000 years if it’s ugly and doesn’t work as a space, just sayin. 

[SteamyTea]

56 minutes ago, Iceverge said:

it keeps most of the water off

Most is not good enough for me.  At my age, I would get worried about waking up with a wet bed.

[maxdavie]

28 minutes ago, CharlieKLP said:

That’s super weird.

Ha! Oh no! Which part? 
Not PDR’s on this - didn’t satisfy exemption rules. 

[Iceverge]

57 minutes ago, CharlieKLP said:

I think there’s a reason we leave technical details to technicians! 

 

Are technical details at a domestic scale not within an architects remit? 

[Iceverge]

53 minutes ago, SteamyTea said:

Most is not good enough for me.  At my age, I would get worried about waking up with a wet bed.

 

There no time in life one is really truly safe from a wet bed, the variations of fluid of course may vary. 

[SteamyTea]

7 minutes ago, Iceverge said:

variations

And flavour.

[maxdavie]

1 hour ago, Iceverge said:

 

Are technical details at a domestic scale not within an architects remit

Yes. And at a larger scale….

Though there are usually architects that specialise at one end of the RIBA work stage sequence and so become expert.

[CharlieKLP]

55 minutes ago, Iceverge said:

 

Are technical details at a domestic scale not within an architects remit? 

There’s no such thing as a standard architect, but most are more generally skilled.
 

I would use standard details for domestic or any other scale. If you’re pushing the boundaries and doing something advanced, then it makes more sense to use a specialist. 
 

Think of an architect as a GP. They know what everything in the body does, but they aren’t going to open you up and mess around in there.

[saveasteading]

What a fun discussion.

 

I should clarify that I am in  favour of interesting places and spaces. How dull it would be if all buildings were entirely designed as weatherproof with no other function.

 

My point though is that no building should leak or rot. If an Architect does not have the skills to ensure this then it should still be their responsibility to engage someone who does.

And they should take responsibility for failure, as the Engineers and contractors more often do.

 

I am well aware that some architecture graduates have not been exposed to practical design and are even told that it is not their responsibility. (Ditto costs).

Other uni's encourage  mixing with engineers and are expected to at least consider practicality.

 

On holiday I go to see Engineering marvels and Architectural triumphs. 

Most of them are very attractive and also very old. 

Some are more modern, and many of these have had issues.

 

Somewhere I have a newspaper cutting from an architectural journalist bemoaning the demolition of a modern church in Glasgow. It always leaked, then it rotted, and it was not much used.

Just before some lobby had it listed as a very special building, the Church authority demolished it. Well done them say I for the final solution, but not for accepting a failed building in the first place.

But to the journalist, the building (and similarly a seminary not so far away) the building was a triumph, and somebody should keep and maintain it. I really can't see how they can suggest that, but perhaps someone can explain that mindset.

 

Maxdavie, I think we are all with you on your project. Innovation is great, and so are proven techniques. I'm happy to keep looking at it with you, and I feel we have just begun.

 

[SteamyTea]

Always remember when looking at very old buildings, they are the ones that survived.  All the others from the same time have vanished.

 

Always worth looking up the work of Prof Richard Gott, III

Edited April 1, 2022 by SteamyTea