Does the BCO have PI Insurance then to cover his "a few cals".
Removal of 2 walls.
- Thread starter Screech20
- Start date
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Hello cAtLeYx, how're you?
OK, maybe it feels like people are ganging up on you, I've noticed that Ree has a bit of a habit of going off topic and getting personal. I try really hard not to do that, and simply try to state facts that give the posters on this forum the ability to make an informed decision. I'm sure you've got a lot of knowledge to offer this forum but acting like the world is out to get you isn't going to do you any favours.
In answer to your questions:
1. To prove a structural element is fit for purpose you can do your own calcs (if you are capable of doing so). There are no laws that stop a person designing their own structural elements should they have the knowledge to do so. Or, as suggested use building control guidance notes. These notes are produced with the explicit intention of enabling builders or DIYers to complete small projects without the assistance of a structural engineer - similar to the Trada load / span tables. Some councils even produce guidance for steel beams for knock throughs.
2. They would know whether or not the installation is sound because they would either have the calcs checked, or refer to the guidance notes. They would also check other aspects of the installation such as supports, restraints, and connections, and, being a building inspector, they should be more than qualified enough to do so. Many building inspectors even have degrees in which they learn some basic structural design.
3. Yes, we could argue about PI insurance, and ideally yes, every design would be covered by PI insurance. However, for minor structural elements such as a simple doubled up joist to support some loft joists, building control, and many home owners, will be satisfied that the information contained in the guidance notes is robust enough to be satisfactory.
Other home owners may not feel this way, only they themselves can decide. However, my (and Ree's) original assertion that an SE is not necessarily required is still correct.
I mean't to add, I wouldn't say my job is one that anybody could do, but some aspects of it are pretty straightforward. Calculating loads is one of them, and something that someone with sub GCSE level maths skills should be able to do, especially for a loft floor.
The weights of timber, plasterboard, insulation, and boarding (if any) are readily available on line. So is the imposed load allowance. Once a load per square metre has been worked out it's just a case of working out how many square metres of load find their way to the beam. Not rocket science by any means.
OK, maybe it feels like people are ganging up on you, I've noticed that Ree has a bit of a habit of going off topic and getting personal. I try really hard not to do that, and simply try to state facts that give the posters on this forum the ability to make an informed decision. I'm sure you've got a lot of knowledge to offer this forum but acting like the world is out to get you isn't going to do you any favours.
In answer to your questions:
1. To prove a structural element is fit for purpose you can do your own calcs (if you are capable of doing so). There are no laws that stop a person designing their own structural elements should they have the knowledge to do so. Or, as suggested use building control guidance notes. These notes are produced with the explicit intention of enabling builders or DIYers to complete small projects without the assistance of a structural engineer - similar to the Trada load / span tables. Some councils even produce guidance for steel beams for knock throughs.
2. They would know whether or not the installation is sound because they would either have the calcs checked, or refer to the guidance notes. They would also check other aspects of the installation such as supports, restraints, and connections, and, being a building inspector, they should be more than qualified enough to do so. Many building inspectors even have degrees in which they learn some basic structural design.
3. Yes, we could argue about PI insurance, and ideally yes, every design would be covered by PI insurance. However, for minor structural elements such as a simple doubled up joist to support some loft joists, building control, and many home owners, will be satisfied that the information contained in the guidance notes is robust enough to be satisfactory.
Other home owners may not feel this way, only they themselves can decide. However, my (and Ree's) original assertion that an SE is not necessarily required is still correct.
I mean't to add, I wouldn't say my job is one that anybody could do, but some aspects of it are pretty straightforward. Calculating loads is one of them, and something that someone with sub GCSE level maths skills should be able to do, especially for a loft floor.
The weights of timber, plasterboard, insulation, and boarding (if any) are readily available on line. So is the imposed load allowance. Once a load per square metre has been worked out it's just a case of working out how many square metres of load find their way to the beam. Not rocket science by any means.
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Hi RonnyRaygun, I'm well thanks
Do we know for example if the purlin\s are also being loaded on either of these walls?
Yes I appreciate the above may be seen as diynot.com suicide, but I think debating an issue professionally is somewhat heathy.
Respectfully yours
Thanks & noted.
Noted - But do you not agree that the Original Poster would not have the knowledge to carry this out for himself.
But you would need to know the load you are supporting to identify the correct material and dimensions from the guidance notes
Would they not need to know the imposed loads to establish if it was sound
Surely he would need to be competent, which generally requires a qualification.
How do we know if a simple doubled up joist is required if calculation have not been carried out.
Do we know for example if the purlin\s are also being loaded on either of these walls?
Yes I appreciate the above may be seen as diynot.com suicide, but I think debating an issue professionally is somewhat heathy.
Respectfully yours
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The truth is we don't know what the OP is capable of. He may well have sound mathematical knowledge but no idea about building. My wife (who has a degree in maths) would have no trouble calculating loads but would want a lot of reassurance about how to work out if it was possible to remove a wall.
Yes, which is why I said earlier that there is nothing to stop him calculating the loads but if he is not confident in doing so then he should consult an engineer.
For a loft floor the imposed load is always 0.25kN/m2. The BCO would know this and guidance notes would allow for the same.
No, the requirement for competence requires you to be competent, not to specifically have a qualification.
I've said several times that the load to the wall would need to be determined. If, and only if, the OP is confident he can determine these loads, then he is perfectly within his rights to calculate said loads and use guidance notes to determine a section size.
Long before I began in structural engineering, I worked for a steel fabricator. I knocked through a spine wall of a house I was refurbishing and installed a 152x89 UB, because it looked about right. One of my colleagues at the time told me I wouldn't necessarily require calcs and he was right. The BCO came round, took one look and said it was fine. He did the same with the steel angle I had installed to support the outer leaf over my french windows.
His esperience told him what was required in this situation, and experience counts for a lot. I've since done many calcs on knock throughs and I know the BCO was right.
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Yes, if I knew the spans required for the new beams, the lengths of the supported joists, and any other load to the wall or joists (such as purlin props), and their positions on the walls or joists.
A plan sketch and photos would help a lot.
A plan sketch and photos would help a lot.
So to summerise - The OP can carryout their own structural calculations after determining what is or is not load bearing and then referring to guidance can ascertain what beam would be required. Or employ the services of a qualified Structural Engineer to provide the Calculations, beam design an cover all of this under his PI Insurance.
Thanks for the input guys. Like I said in a previous post, I didn't want this to turn into an argument, but hopefully that has now passed.
I now understand that calc could be done by either a SE or myself. In this case, i'm going to go with a SE. As this is my first go at something like this, i haven't got a clue where to start with calcs, so i'll be much happier having someone in to tell me what wall is load bearing and calculate what needs to be calculated.
This is good to hear, this is the route i would like to take.
I had already thought about whether the floor would take it or not, so I thought about laying a slab for the new wall to be built off of...?
I've done a little bit of a measure up, and i'm confused about span lengths - My ceiling joists are 100x50. Looking online, the max span they can run is 1.8m... most of my rooms are bigger than that... am i looking at the wrong tables?
Cheers
I now understand that calc could be done by either a SE or myself. In this case, i'm going to go with a SE. As this is my first go at something like this, i haven't got a clue where to start with calcs, so i'll be much happier having someone in to tell me what wall is load bearing and calculate what needs to be calculated.
This is good to hear, this is the route i would like to take.
I had already thought about whether the floor would take it or not, so I thought about laying a slab for the new wall to be built off of...?
I've done a little bit of a measure up, and i'm confused about span lengths - My ceiling joists are 100x50. Looking online, the max span they can run is 1.8m... most of my rooms are bigger than that... am i looking at the wrong tables?
Cheers
You will get a bit more than 1.8m from ceiling joists - about 2.15m if 400mm crs and C16. This takes into account a long term load of 0.25kN/m2 and a short term point load of 0.9kN (around 90kg).Any more light on this?
Cheers
If the point load is ignored (shouldn't be but sometimes is) then you will get about 3.35m max span. It's possible - especially if your house is older - that the joists haven't been designed for a point load and this is why they span further than stated in the tables.
So are you suggesting a Structural Engineer is not required here and if so what advise would you have offered the Original Poster.
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