Do garage wal need bracing

[GeoffJ]

Hi

I am helping out an friend with an aggressive developer next door.

The two houses have detached but joined garages. The builder (122) wants to remove their garage to make room for a side extension to the house.

The original garage walls are of 4" brick. Small integral pillars (4") are installed in the front area. Originally it would have been like the diagram below (I guess this is as standard as you can get for joined garages). Beams connect the outer walls (passing through the central wall) to support the roof. The roof is mainly of sheeting material but there is a small decorative clay tile roof at the front.

Many years ago the owner at 124 built another garage at the rear of the existing. This meant knocking down the rear wall and installing a concrete beam so that a single open space is created. So the current state is as follows

This has been the state for a lot years and it appears quite stable. Bracing is achieved due to the rear wall of 122 and the connecting beams joining the outer walls.

So the builder wants to wholly remove the garage at 122 to leave the following

The PW surveyors are happy with this and see no problems. They say that joined garages being split is a relatively common requirement and this is the standard way it is done.

I have tried to tell them that the resulting building will be unsafe as it has poor bracing. My view is that the front part of the garage will be susceptible to toppling if a side force is applied (eg high winds, materials stacked against the wall, or a vehicle knocks it).

The PW surveyors have decided to ignore my concerns for the lack of bracing. I have asked repeatedly that if the building owner takes the view that no bracing is required then a structural engineer must confirm this view. The risks to property and life are clear.

We have not quite reached deadlock at they are still completing the draft PW agreement that will formalizing their view.

Any views from this panel of experts
Am I wrong about bracing?
Is it worth taking this to arbitration if they will not either install bracing, or get an expert to support their view?

Thanks in advance
Geoff

 

[GeoffJ]

Also meant to say that the rear extension is also made of brick walls (4") and sheeting material for the roof

 

[Footsoldier888]

Geoff I think you are worrying unduly because at the point of constucting the build the Building Control Officer is there to ensure the works are structurally safe. If the BCO is unhappy in any way about the stability he will demand that structural calculations are done and double checked by the council. Perhaps more importantly a test of the foundations on the existing garage will also take place.

I really don't think you have anything to worry about and the fact the developer has entered into a PW agreement shows he is acting in a responsible manner.

 

[GeoffJ]

Hi Footsoldier888

That could work - is there a way that we can verify that the Building Control officer has been properly informed of the risk and been given fair opportunity to consider the risks?

(This is also the potential issue that the BC officer could fail to act through willful neglect or simply not thinking about it, and then there is no comeback on anybody should the garage collapse.)

 

[Footsoldier888]

Yes - you can ring them and chat to them when they do the inspection.

There is an immense amount of comback because you say you are in a PW agreement, also the BCO is a statutory body.

As for the bracing, I am not totally clear what you mean. The piers will stop the wall blowing down and the joists tie the walls together forming a very strong box. Garages don't blow down because they are low structures tied with a load of joists. I think if you walk around your local area you won't see any garages blown down!

If 122 wants to remove part of the pier say they would replace it with a steel column say, if that is your concern re bracing.

 

[GeoffJ]

They intend leaving the integral pillars in the front section. The pillars are designed for vertical load bearing (clay roof tiles). They will not be providing much in the way of resistance to side force.

I totally accept that standard garages don't blow down.

New 4" walls are built to limited height and length because they are not very good at resisting side forces. For height or length we build pillars and/or insert 90-degree bends so they can resist side forces.

Garages are normally 1 car long with a wall that provides full bracing at the closed end. I accept that a standard garage built of 4" bricks would be stable.

In this case the garage is 2 cars long. The rear half is braced because of the rear wall. But, can we rely on the rear wall to brace the front half of the garage?

Then we could consider that the clay tiles at the front cause the heaviest part of the roof to be at the front, where it is most distant from the bracing wall, and also the wall area most pone to being hit by vehicles.

It is just a concern that I think they should properly consider and close out (either via design, or structural engineer's opinion ). Currently they appear to be signing it off as acceptable.

The BC suggestion should work to resolve this.

Regards
Geoff

 

[Footsoldier888]

Well as I understand things the concrete beam will tie the walls together at that point. As long as there are joists tying the walls together at regular intervals the walls will be braced.

 

[^woody^]

Is not a problem. Single garages just like the one that will remain are common, and do not rely on walls as in that attached garage.

 

[GeoffJ]

Well as I understand things the concrete beam will tie the walls together at that point. As long as there are joists tying the walls together at regular intervals the walls will be braced.

The concrete beam at the connection between the old garage and extension will tie the walls together - but it does not brace the walls - that is the walls can move together

I also raised the issue that the existing beams are tied to the outer walls. Currently they pass through the central wall, or rests on it. If the joists are to brace the walls then it seems logical to me that the builders must ensure that the beams are fixed to the exposed wall.

Regards
Geoff

 

[Footsoldier888]

Geoff I must admit I was thinking the same as you about the need to pack the joists. However the point is that if that was neccessary it would be included in the schedule of works in the PWA. Perhaps it is included in a catch all phrase such as making good the wall? Obviously that would have to be addressed or you would have water penetration too. Then you might have to have some form of cladding such as a facia board.

Are you 100% sure it is one piece of timber going through both garages because it would have to be very deep to span what is say 6m for argument? It would cost a lot more to build like that which is why I am asking. Are you quite sure they don't meet on the party wall???

As for the walls moving together - I get your concern but the bonding of the wall itself resists this plus the weight of a wall supported by what I guess to be a few triangular joist rafter thingies that your shallow pitch roof sits on. Single brick garden walls blow down because they are unsupported but a garage wall has the corners, the tied beams and the weight and force of the roof to support it. The garage concept is well proven!

The rear wall of No 122 does nothing structurally for your building. If No 122 put a lintel in the back wall it wouldn't affect you.

Something that is of more concern is after taking down his garage I presume he is going to build something near your wall. My neighbour did this with an outbuilding and now 20 years on the facia is rotten and he can't replace it as it is under my asbestos roof and the gap between our buildings is too small. I give this as an example so as to think about the outer side of your wall if you have a similar situation.

 

[GeoffJ]

Thanks for a detailed explanation footsoldier888

The joists could be in two pieces and you may be quite right.

I will calm down and let the BC bod review.

 

[tony1851]

Storm in a teacup.

 

[Footsoldier888]

LOL tony. The joke is I managed to convince myself a couple of weeks ago that my neighbours steel was about to bring the party wall down until some sensible folk on here posted a similar sentiment. I find it's a lot easier to see other peoples issues than one's own.