Increase loft space

[Garden Shed Projects]

Mrs GSP has requested some additional loft space for storage of seasonal stuff, kids clothes and other items. I live in a fairly modern house with roof trusses in the below configuration.

She would like me to investigate making alterations to something similar to this configuration.

Is is possible/ feasible to modify premade roof trusses, I am assuming it will require an engineers design as a minimum. Or am I looking at a reroof with new trusses purpose made to suit my requirements.

Any experience or thoughts would be greatly received.

 

[Adam W.]

It depends on the size of the rafter on your original truss, the timber grade, their spacing and the load (your roof covering).

If I was doing that, I'd at least add a collar at 2/3 height to stop the rafter from deflecting.

 

[RichardG]

You have what's known as a fink truss and you need to convert it to an attic truss. That's the core of a loft to room conversion so yes it can be done but it's not trivial. Fink trusses are used because they offer the best load and span whilst using the minimum of materials, ie. they're the cheapest. If you planning on using the space then you'll probably also need to upgrade the floor timbers (currently the ceiling). Definitely need a designer and building control approval, you'll also need to notify your house insurer.

There's quite a few examples on the net, e.g. What can you do with a loft full of truss rafters? Loft Conversion Project!

Modern Fink Truss Conversion

 

[Inspector]

Do you have self storage places like we have. Pay a monthly fee depending on the size of the unit and access it whenever you need to put things in or take out. You can rent a long time for the cost of remaking the top of your house.

Pete

 

[Sachakins]

That's no simple task, requires structural calculations, building control inspection.
Get it wrong and you could end up with no roof, bulging walls or pile of rubble.

Try hunting for loft truss shelving, like this, but cheaper elsewhere.
https://www.loftzone.co.uk/steel-trussshelf/

 

[clogs]

unless ur house is detached dont even think about it.....
to many regulations to jump thru.....
just get a bigger shed....

 

[mikej460]

In my humble experience the more space you have the faster you fill it; the best solution is to have a ruthless clear-out. We had a yard sale a couple of months ago and cleared out a whole load of stuff we never used.

 

[Spectric]

This is something that can be done, but will not be cheap. Modern roofs use these pre made roof trusses to minimise cost, they use the least volume of timber to deliver the required load bearing capacity and illiminate the need for a qualified carpenter to build the roof, just need builders to throw it up. The trusses are only capable of taking the load when intact, all members are either in compression or tension held together with nail plates. So you can have the Fink trusses taken out and replaced by room in roof or attic trusses which are made of more substantial timber and will weigh almost twice what the old ones do. They will leave part of the old trusses in place as the support your ceilings and put the new ones next to them, new facia's, sofits and guttering and reuse the original tiles but new underlay and battens. All sounded great for me until the quote, so I never bothered.

 

[Doug71]

I worked on a loft conversion a few years ago where we made some large plywood i-beams which were about 1200mm high. They ran the full length of the roof supporting the rafters like a purlin, all the zig zag members were removed from the trusses, think we also put some kind of ties in the top. It allowed it to be done without having to do any work on the roof externally. It was all done properly to approved drawings.

 

[Garden Shed Projects]

What has been said reinforces what I already suspected. We are looking to have a substantial upgrade and extension on the house in a couple of years and are in discussions with an architect. He thinks it is feasible which is fuelling the wife’s thoughts of getting it done.

I hadn’t considered the inspectors idea of self storage which may be worth looking into as an option. My preferred option would be to go with mikej460’s suggestion and have a ruthless clear out but I haven’t managed to gain traction with that idea yet in 20 years of marriage.

 

[TFrench]

architects are very good at thinking things are feasible as long as you're paying them.

 

[Sandyn]

You aren't gaining any volume, all you are getting is a more 'usable' volume. If it's just for storage, the most cost effective is to floor what you have and design/ buy some clever storage solutions. Have good access to the space and lots of lighting up there.

 

[Trainee neophyte]

Questions I would be asking:

1. Would it be cheaper to buy a different house? (Now that is a good argument to use on the wife, unless she suddenly gets excited and wants to move!). What will be the increase in value vs the cost?

2. How much stuff do you need to actually store? What's the volume? Would a few sheets of chipboard between trusses do the job, assuming there is sufficient strength to take the load?

3. What is the value of the stuff you want to hide away forever until the kids have a massive clear out after the funeral? Is it cheaper to throw it away, and buy again when/if you need a fifteen year old, slightly foxed, imitation Prada handbag?

If I was going to spend huge amounts on a loft conversion I would want a huge, shiny new room for my investment, not just a big wardrobe. Think of all the tools you could have in your new workshop space.

 

[Rorschach]

A lot of good points here.

Personally before undertaking something like this I would get a quote, and then investigate the cost of either buying a small lock up locally or the cost of renting a storage space. Around here I can get a nice size little storage locker for about £5 a week, so lets keep the numbers simple and say £300 a year, 10 years of storage, £3000, I'd be willing to bet the roof conversion would cost an awful lot more than that.

I went one further and purchased a cheap garage as circumstances were good at the time. Free storage for as long as I like and as long as I keep some very basic maintenance I will be able to sell it in future for more than I paid for it. A loft conversion won't necessarily recoup it's costs and is less flexible (I can store anything up to the size of a medium car)

 

[scholar]

With no actual interest in a loft conversion, I stumbled on a YouTube channel called Ecotrus or Build it with Rob that specialises in exactly this conversion using steel joists and rafters.

it is strangely fascinating seeing the conversion process and the space gained.

this would be worth you looking into, I think.

Cheers

 

[Garden Shed Projects]

Questions I would be asking:

1. Would it be cheaper to buy a different house? (Now that is a good argument to use on the wife, unless she suddenly gets excited and wants to move!). What will be the increase in value vs the cost?

2. How much stuff do you need to actually store? What's the volume? Would a few sheets of chipboard between trusses do the job, assuming there is sufficient strength to take the load?

3. What is the value of the stuff you want to hide away forever until the kids have a massive clear out after the funeral? Is it cheaper to throw it away, and buy again when/if you need a fifteen year old, slightly foxed, imitation Prada handbag?

If I was going to spend huge amounts on a loft conversion I would want a huge, shiny new room for my investment, not just a big wardrobe. Think of all the tools you could have in your new workshop space.

I have considered boarding it out however the additional lock up or self storage is definitely something I am going to look into. The reality of that though is we are more unlikely to visit it and sort through the stuff if it’s not on the property. Although We Currently have stuff that’s been boxed for over 10 years without being opened.

Currently the stuff is stored in my garage/workshop and it would be good to have the space back so I do have a vested interest in feeding her hoarding needs in some other way.

Likely hood is we will get a quote and I hope it will be high enough to encourage some value engineering.

 

[Rorschach]

If you haven't needed it in 10 years, there is a very good chance you won't ever need it.

I am getting better at clearing out stuff, easier with household stuff but very difficult with tools though as just because a tool isn't used for a couple of years doesn't mean it isn't useful. I only use my tile cutter about every 5 years for example.

 

[Spectric]

You aren't gaining any volume, all you are getting is a more 'usable' volume. If it's just for storage, the most cost effective is to floor what you have and design/ buy some clever storage solutions. Have good access to the space and lots of lighting up there.

Good idea but check what weight can be safely stored, these roof structures are designed to support the roof and not a large weight inside. When we had tanks in the loft they used to build a platform that had 6x2's spaning many trusses to spread the load to support the weight, perhaps a similar idea could help solve your storage problem.

I remember when getting a quote to convert my loft that like everything I did not just accept this was the only solution and did some investigation but none were simple or cheap. These trusses came about for two main reasons, cost and the ability to span across the outside walls without any structural support in between, this allowed all internal walls to be non structural studwork. So it was a win win for the builders as it saved money on building decent internal walls, the trusses required unskilled labour to fit and were cheaper than a roof made on site by a skilled chippy. The main issue faced was getting lengths of timber long enough to span the walls, this was solved by joining shorter lengths in specific locations where the stress was minimal. So just modifying your existing trusses although initially it looked an easy way to go is fraught with big risk. To fully understand the issues you need to understand how the fink truss works so you know what to expect if you take a saw to it!

All the mass is supported by the outside walls on which the horizontal member sits, the actual roof sits on the two chords that form the overall triangle. The two outer supports are in compression and are taking the load from the roof into the horizontal member, to counteract this force the two inner supports connected to the apex are in tension and support the point where the two supports connect to the horizontal member and the apex is the strong point. So you find the connectors on the horizontal member are in between these two points where the supports connect as it is a lower stress point.

So if you wanted to turn a fink into an attic truss you basicaly remove the two inner supports and make the outer supports upright, job done but now your horizontal member is trying to hold the roof up without any support from walls below. The other consideration pointed out to me by an architect was with regards to the pitch, what may be an acceptable pitch for a fink truss on a given span may not be ok for an attic truss. As the span reduces so the pitch increases, this was the problem for my roof, the pitch would need to be steeper and now the brickwork on the gable ends needs redoing so more cost. I just gave up, not worth doing at my age so I built another shed, much cheaper option.

 

[Spectric]

I am getting better at clearing out stuff,

How many find this easier as you get older, I am now looking at things and being honest with myself in as much as realistically not only how much time do you have left but how much of this time will you be capable of using it. You can only do so much, stretching yourself to far just means a lot of things are going on but without much output. I have given up on photography, you need really good eyesight, it is probably more expensive than woodworking and very time consuming both out in the field taking images and then post processing so anything related can go, cash for my woodworking. Decluttering could become fun, you find stuff you had forgotten you had and big problem is where to sell, fleabay is no longer what it once was.

 

[Jameshow]

I worked on a loft conversion a few years ago where we made some large plywood i-beams which were about 1200mm high. They ran the full length of the roof supporting the rafters like a purlin, all the zig zag members were removed from the trusses, think we also put some kind of ties in the top. It allowed it to be done without having to do any work on the roof externally. It was all done properly to approved drawings.

I had a 60's self built house like this.

Perhaps a structural engineer might be able to design it for you?

Cheers James