I would like to make better use of my loft area for reasonably light storage.
I understand that chipboard flooring is quite heavy and that I should do some strenghening if I want to alter the positioning of the Collars. binders and bracing struts.
I really would like to be able to remove these and of course replace them with something else that didnt get in the way so much.
There is a center load bearing wall.
My loft "usable" area is 6.2mtr x 3.1mtr with another 1.85mtr from the purlin to the eaves each side that could be used for storage/access after modification and is of 1960's vintage so has 4"x2" joists at 16" centers.
There are 2 off 3"x5" purlins with 3 off 2"x3" bracing struts and
4"x1.5" collars with 2 off 4"x2" binders sitting on the joists.
The rafters are 4"x2" at 16" centers.
The maximum height I have at present to the apex from the joist tops is
2.2mtrs
Here are some pics to help.
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from getting an architect or structual engineer involved can anyone give me an idea what I should be aiming to do to in order to be able to remove the offending timbers please.
I thought we all had hi speed broadband these days so I didnt think I would have to reduce the pic quality. Its not like I tried to post them to a newsgroup. I am a little dissapointed in that the only replies have been completely counter productive. This used to be a really friendly group full of people who would help with info but maybe they all have Mondays off.
The message from snipped-for-privacy@invalidaddress.com (MikeT) contains these words:
I wouldn't call them counterproductive. They were reasonably polite comments about the photos. I view at 1280x1024 and they still won't fit without shrinking.
I've no idea. Does the sender have any control over that? Not all the pictures I receive shrink automatically. I try to remember to shrink pictures I send but sometimes I forget. The recipients all let me know :-)
Same reason software programmers and coders (read Microsoft) don't spend time squeezing the maximum product into the smallest program.
The hardware available usually by far exceeds the the software requirements so they prolly went straight from cam. to web without stopping for compression on the way.
Didn't bother me, they popped straight up without delay, but they would have been more acceptable for the masses at half that size if not smaller I agree.
On Mon, 19 Jun 2006 22:24:49 +0100 someone who may be "Mary Fisher" wrote this:-
The person who puts them on the web controls the size of the file. Of course they may be entirely unaware of this and think that just sticking something from a camera onto a server is all they need to do.
If they are displayed in a web browser then they will shrink if the browser is set to do this, otherwise they will not.
Hi Mike, at the risk of appearing needlessly helpful...
I'd go with the architect or structural engineer if I were you.... BUT..
You can, with a bit of thought and the necessary skills, do (most of) it yourself, but any changes to the roof structure (removing the collars, struts, bracing etc.) will require building control notice and approval, party wall act notice and approval by your neighbours (at *your* expense). Remember, the current joists are also holding your house together (they take the outward load of the roof at the top of the walls) and *CAN NOT* be removed even to allow the fitting of larger replacements without adequate precautions to prevent collapse of the building... it does happen.
I'm contemplating doing much the same with the loft in the New House In Prospect (offer accepted, no contracts yet...) which has a remarkably similar but rather larger loft structure, and anticipate having to add steel purlins secured to the end gable walls (span tables in the older building regs document A, here:
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will give you an idea of the BCO's requirements, which rule out simple unsupported wooden purlins on spans much over 9 feet... ) as I'll be removing the originals, which are *exactly* where the means of escape windows will have to go if I want it to meet the BR's...
The current joists you have are *ceiling* joists, and are only enough to support the plaster below and the insulation, so you'll be looking at installing new floor joists, probably minimum of 8"x2", supported on load-bearing walls - again the document A tables will indicate joist sizes and spans for various loadings.
If the "storage" in the loft is likely to be used as a habitable room (even for "hobby" use), it'll need light and ventilation, access (proper stairs), insulation, means of escape, fire resistance to be approved, too - this is where it gets *really* hard to meet the conflicting bits of the regulations!
Hope this helps,
Dave H. (The engineer formerly known as Homeless)
PS - nice pics, good clear views, no problem with file size, as I'm in the
21st century with a proper broadband connection.... ;o)
Sorry your perfectly reasonable and valid thread went somewhat awry. I do wish the posters who 'claim to know better' would aim their views at some of the totally off topic sh*te that gets posted here instead of you.
I was recently looking at doing much the same to my loft - the main point for me was that I wanted to put in a proper staircase to make it properly accessible storage space.
I soon discovered that in doing so, you make the loft 'habitable space' and so building control comes into effect. I considered just doing it on the sly, but then started thinking about what if we have a fire - how would the insurance company react etc.
Long story short I got an architect in to do the drawings, he instructed an engineer for the loadings and all was submitted to building control and subsequently approved.
Our loft area is approx 7m x 7m. The existing roof has a single purlin each side and just the two collars. The purlins are embedded in the gable ends.
The approved construction is to replace both purlins with steels and replace the two existing collars with one at every truss but above head height (ie, tiny little things almost up at the ridge).
I dont know what the diagonal beams are called which go from the purlins diagonally down to the rafters but these are to be replaced by upright steels which sit on load bearing walls below (one per purlin).
In order to fit in a full size staircase we need to move an upstairs wall (dense block construction) and so to maintain load bearing down through the house we need to also insert a steel in a ground floor ceiling and build the newly moved upstairs wall on top of that in block
- the steel to the purlin above then sits on top of the block.
AIUI the average roof can weigh something like 10 tons or more (maybe someone can be more accurate on that) and as the only other helpful poster (DaveH - well done!) has pointed out it is a major structural part of your house.
I know I've gone on a bit - but all of the structural work above (DIY'd of course) including the architect, engineer, building control approval and materials is costed at 2 grand. I think that's more than reasonable for the peace of mind.
|Guy King wrote: | |>> They shrank automatically on my screen. |> |> They do on mine, too. The point is that few people have monitors large |> enough to view them at full size - so why publish them at that size. | |Same reason software programmers and coders (read Microsoft) don't spend |time squeezing the maximum product into the smallest program.
|The hardware available usually by far exceeds the the software |requirements so they prolly went straight from cam. to web without |stopping for compression on the way.
They call it program bloat.
Which is great if *everyone* gets a new all singing, all dancing machine
*every* year, with the fastest broadband Internet access, etc. etc. Many have to make a machine last quite a few years, and these are slower than the latest machines. I use the Guardian as my browser home page and that has got slower and slower and slower over the years, as they have added animated gifs and such useless rubbish to the adverts. I will soon be forced to get a new machine, and broadband, just to get reasonable speed out of the same old sights which used too work.
Please get an engineer involved. You will save yourself so much hassle. I'm an engineer and we see quite a lot of jobs where the home owner has altered the roof structure without involving a professional. I've yet to come across one that actually worked when the design was carried out. If you are going to do a job, do it right. You will have difficulties selling your property in the future and you may end up with a dangerous structure, not something I would want my family to live in. Please don't make the mistake of expecting any old joiner to know what will work. If you are altering the structure of a building you will need a building warrant.
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