Wall coming down. Need Structural Calc done any advice

[happyhero]

Hi I want to remove what I think is a structural wall to make 2 rooms into 1. I live in a 1933 mock Tudor semi detached house with cavity walls and a suspended timber floor. This floor is about 1 foot above the dirt or concrete, can’t really be sure as it is so dirty under the floor.


I know that normally people have a pillar at each side, creating an arch or square arch so that there is wall each side to support the beam but I want to do this differently, I would like it to have no pillars.


Furthest from the neighbour one room is narrow than the other so that if the wall was removed it would create a sort of dog leg shape I think they call it. I think this creates one pillar possibly.


At the neighbours side I know the wall is 2 bricks thick and I was wondering if it would be possible to cut some sort of spreader plate into the bricks on our side to support the beam, thus giving the impression of one giant alcove between what would have been the 2 fireplaces (1 in each room but one has already been removed in the past).


I have been told by my council to first get the structural calculations done for beam size etc, and then send in a Building Notice Application and that could be approved within 48 hours. I am amazed the last time I did anything I had to wait 8 weeks and that was just for permission for an awkward shaped shed. I thought they would be bothered that I was wanting to mess around with the party wall is this not a problem? Does it not require any paperwork for the party wall?


The Building Notice form seems quite small compared to what I saw years ago, much simpler, does this mean its quite simple now or am I being fooled?


Also people have told me I don’t really need to get an architect and I will pay through the nose for this, so I am looking online for this and it appears that some will do it for less than £100 via email, I know you could say you get what you pay for but there apparently are many companies doing it this way and have all the guarantees in place etc. I cant understand how they can asses my house and beam size from a distance, or is it fairly simple I thought they would be looking at the construction of the walls, the ground underneath, the weight of what is on top, ie attic extension or not etc etc,?


If they are just going to ask me information and base it on that, will the council really trust that? The companies often guarantee 100% council approval, so it implies that????


Can they asses it like this?


Could you recommend anyone online?


Do I need a Architect?


Any help/info appreciated.

 

[^woody^]

You could do without any piers if the person doing the calcs knows what he is doing. For less than £100 via email, I suspect someone will just put some figures into a pirated program and out will come a 102x203 UB. They wont consider much else other than the loadings. and probably not any fire precautions to the beam or means of escape

The building notice form has always been simple, and it relies on you knowing what to do and the inspector checking it - and hopefully not telling you it's wrong

The Party Wall Act will apply.

 

[RonnyRaygun]

There are a number of issues to consider here, but in principle it is possible to remove the spine wall completely.

1. Is the remaining unbuttressed length of party wall less than nine metres? If not, you will need something (a pier, post, or box frame) for stability. I'm guessing it is less than nine metres as you say one chimney breast remains.

2. Even if the unbuttressed length is less than nine metres, some local authorities will insist on a pier, post, or box frame.

3. Does the opposite wall have a foundation? Often non load bearing walls do not have foundations. The wall may or may not be load bearing; the point is we don't know.

It's not a problem cutting into the party wall to install a beam - a padstone or a spreader plate would be required. Technically you should follow the Party Wall Act, although often people on this forum will tell you not to bother, especially for relatively minor works. I'm inclined to agree. The council won't care if you've applied the Party Wall Act, as long as they can see that your scheme works structurally.

No, you don't need an architect - you just need a structural engineer.

Be careful if you appoint "someone off the internet" - ensure that they will provide all of the calculations that your LA requires. The £100 price may well be for just the beam design - they should be designing padstones, and checking loads to foundations etc as well. You won't be getting much more than a beam design and possibly the padstones for £100 I am sure.
They may well be making assumptions that could lead to a very conservative design, and they will require information from you, such as wall thickness and type, floor spans, span of attic joists, any purlin struts or similar that may apply roof load to the wall. You may have to send them photos too. Obviously they will be relying on you to provide them with accurate dimensions etc.

 

[^woody^]

Ronny, have you read the article in the latest CROSS newsletter regarding stability of terraced buildings when structural cross walls are removed? It's interesting

To the OP
"When there is a structural engineer it is their responsibility, even if appointed for only one unit within the terrace, to consider the wider implications of wall removal .......... When there is no engineer, which may well be the case, then overall stability can be compromised and there are many examples of uncontrolled modifications works leading to collapse"

 

[RonnyRaygun]

Ronny, have you read the article in the latest CROSS newsletter regarding stability of terraced buildings when structural cross walls are removed? It's interesting.

To the OP
"When there is a structural engineer it is their responsibility, even if appointed for only one unit within the terrace, to consider the wider implications of wall removal .......... When there is no engineer, which may well be the case, then overall stability can be compromised and there are many examples of uncontrolled modifications works leading to collapse"

I haven't read it, no, but this would be exactly the reason why many councils insist on box frames or similar when a spine wall is removed.
The nine metre rule may well only apply to new build where there is more certainty that there is sufficient strapping to ensure lateral loads are distributed to the outer walls. I need to check that. Adding additional strapping may be one way to appease the council, but even that might not be enough.

 

[happyhero]

There are a number of issues to consider here, but in principle it is possible to remove the spine wall completely.

1. Is the remaining unbuttressed length of party wall less than nine metres? If not, you will need something (a pier, post, or box frame) for stability. I'm guessing it is less than nine metres as you say one chimney breast remains.

2. Even if the unbuttressed length is less than nine metres, some local authorities will insist on a pier, post, or box frame.

3. Does the opposite wall have a foundation? Often non load bearing walls do not have foundations. The wall may or may not be load bearing; the point is we don't know.

It's not a problem cutting into the party wall to install a beam - a padstone or a spreader plate would be required. Technically you should follow the Party Wall Act, although often people on this forum will tell you not to bother, especially for relatively minor works. I'm inclined to agree. The council won't care if you've applied the Party Wall Act, as long as they can see that your scheme works structurally.

No, you don't need an architect - you just need a structural engineer.

Be careful if you appoint "someone off the internet" - ensure that they will provide all of the calculations that your LA requires. The £100 price may well be for just the beam design - they should be designing padstones, and checking loads to foundations etc as well. You won't be getting much more than a beam design and possibly the padstones for £100 I am sure.
They may well be making assumptions that could lead to a very conservative design, and they will require information from you, such as wall thickness and type, floor spans, span of attic joists, any purlin struts or similar that may apply roof load to the wall. You may have to send them photos too. Obviously they will be relying on you to provide them with accurate dimensions etc.

Cheers Woody and Ronny, from what you say you are sort of confirming my doubts about the internet method so I think I will have a real person in.

1. To answer your questions the span of the smaller room is 3.4m and the larger room is about 1/2 meter bigger.

2. Where one rooms is bigger than the other you end up so that if you look from the bigger room side you will have 1/2m of wall staying put which comes up from the messy real floor below, would this support one end of the new beam? I hope the local authorities do not ask for any kind of post as I really want the long smooth wall to the point I am even wondering of getting a new wall built in front of the existing wall which maybe could conceal any pillar, the wife fancies a brick wall on show, yes I know i would lose 4" of the room if this were to be done.

3. Not sure what would qualify as foundations but I do know that the load bearing wall goes all the way to the real messy ground I mentioned. Wouldn't foundation be wider than the wall ie visible and would or could that differ if built in the 1930's?

Could foundation be below the messy bit and if so how could I tell they were there?

Also if I unluckily got involved in the Party Wall Act, what would that mean for me, in costs and extra work?

 

[RonnyRaygun]

Cheers Woody and Ronny, from what you say you are sort of confirming my doubts about the internet method so I think I will have a real person in.

1. To answer your questions the span of the smaller room is 3.4m and the larger room is about 1/2 meter bigger.

2. Where one rooms is bigger than the other you end up so that if you look from the bigger room side you will have 1/2m of wall staying put which comes up from the messy real floor below, would this support one end of the new beam? I hope the local authorities do not ask for any kind of post as I really want the long smooth wall to the point I am even wondering of getting a new wall built in front of the existing wall which maybe could conceal any pillar, the wife fancies a brick wall on show, yes I know i would lose 4" of the room if this were to be done.

3. Not sure what would qualify as foundations but I do know that the load bearing wall goes all the way to the real messy ground I mentioned. Wouldn't foundation be wider than the wall ie visible and would or could that differ if built in the 1930's?

Could foundation be below the messy bit and if so how could I tell they were there?

The load bearing spine wall will almost certainly have a foundation; whether or not the foundation is substantial enough to cope with the additional loads from the beam, it's impossible to say without inspecting what is there and doing a calculation. The foundation won't necessarily be visible as it will probably be below the level of the oversite.
If it so happened that the foundation was not of a sufficient size, you could underpin locally, although it might be just as easy to rebuild the section of wall on a new foundation.

Also if I unluckily got involved in the Party Wall Act, what would that mean for me, in costs and extra work?

A party wall surveyor would charge you a lot of money to produce a document that sets out your rights and responsibilities with regard to the party wall, working hours, what happens in respect of damage caused, and access arrangements.
Your neighbour is also entitled to engage a surveyor, and you will have to pay their fees too. You might agree to both use the same surveyor.
The party wall agreement could end up costing as much as the works being carried out in a small job such as this.