Disagreement on spec by engineer

trace51

We have plans drawn up by an architect for a new build but needed structural drawings. We asked the architect to recommend an engineer and went with his recommendation (we were trying to rush forward due to earlier delays, we really should have looked for several quotes but that is our fault).

We sent the drawings to several companies to quote for a foundation slab. Two well known companies came back to us with the same issues around the detail - all internal walls treated as load bearing walls at foundation level, large amounts of concrete that are unnecessary (could just be underneath a structural pillar rather than the width of the room), should use an 'L' piece instead of a 'G' as this would save costs with less waste when cutting. The engineer was slow to get back to us and unwilling to engage with the foundation companies. They suggested that if the foundation companies provide an ancillary cert we can follow their advice, although they disagree with the advice. The foundation company referred us to an engineer who would redo the drawings at less cost than the original engineer.

Basically, my question is, how do we know who to trust? I am sure it is clear from the post that we only have basic building knowledge so are relying on the professional expertise of those we are paying. We don't want to waste money on unnecessary measures in the foundation, but don't want to have to pay for new drawings either. Any advice/thoughts would be appreciated!

T-Maxx

A bit like going to the gp, then going to the pharmacy to be told that the gp is wrong...

Gumbo

T-Maxx wrote: »

A bit like going to the gp, then going to the pharmacy to be told that the gp is wrong...

Had a little chuckle at this but I couldn't have put it any better.

OP, listen to whoever is signing off on the structure.

Effects

T-Maxx wrote: »

A bit like going to the gp, then going to the pharmacy to be told that the gp is wrong...

trace51

Both parties are engineers, with equal qualification, so I don't see the relevance of your comment. I don't have the knowledge to determine which of the two, if any, is giving me the best advice.

I can have the original engineer sign off or I can go to another to sign off the proposed changes.

Metric Tensor

Doctors differ .....


All engineers will have slightly different ways of doing the design work and provided they have professional indemnity insurance and are willing to sign the appropriate certificates there's very little you, as a lay person, can do to check their designs short of getting another engineer to review them.

The contractors who install the concrete and steel are rarely equipped to design them or sign off on them and their advice re design decisions should be treated accordingly.

Your engineer most correctly should not engage with second guessing from someone who won't be signing off on the project. There is no problem with informed discussion of course but the buck, the certification and the decision rests with the engineer in charge.

If you want to dispense with one engineer and employ another you're free to do that of course provided you pay for the work done to date.

Finally I'll add that if you buy a cheap TV and it fails you can buy another to replace it ... If you put a cheap foundation under your house and it fails ......

Penn

trace51 wrote: »

We have plans drawn up by an architect for a new build but needed structural drawings. We asked the architect to recommend an engineer and went with his recommendation (we were trying to rush forward due to earlier delays, we really should have looked for several quotes but that is our fault).

We sent the drawings to several companies to quote for a foundation slab. Two well known companies came back to us with the same issues around the detail - all internal walls treated as load bearing walls at foundation level, large amounts of concrete that are unnecessary (could just be underneath a structural pillar rather than the width of the room), should use an 'L' piece instead of a 'G' as this would save costs with less waste when cutting. The engineer was slow to get back to us and unwilling to engage with the foundation companies. They suggested that if the foundation companies provide an ancillary cert we can follow their advice, although they disagree with the advice. The foundation company referred us to an engineer who would redo the drawings at less cost than the original engineer.

Basically, my question is, how do we know who to trust? I am sure it is clear from the post that we only have basic building knowledge so are relying on the professional expertise of those we are paying. We don't want to waste money on unnecessary measures in the foundation, but don't want to have to pay for new drawings either. Any advice/thoughts would be appreciated!

The foundation company may only be looking at what is required from the point of view of the foundations, whereas the engineer will likely have taken the structure as a whole into consideration as part of the design.

In addition, the foundation company may have referred you to another engineer who would redo the drawings, but they're drawings and design that have already been done by your current eng. Which means you're either paying them both to do drawings/design (as your current eng has already done them and therefore should be paid for same) and therefore likely not saving as much on the reduced foundations, or you're going to not pay your current eng, which is unfair.

Opinions can vary as to the best spec to address certain issues. If the existing spec is still within your budget and has already been allowed for, changing it now could result in design/specification conflicts further down the road.

Calahonda52

OP: What is the incremental cost of the " large amounts of concrete that are unnecessary" and the G versus L footing

The reality is that simple foundations, even those with "large amounts of concrete that are unnecessary" are a much better job than these ones you describe as the additional complexity of their design, when you factor in the cost of executing correctly this complexity for:

1. marking out and digging out the subsoil,
2. setting up the formwork,
3. bending and fixing the rebar
4. pouring and vibrating the concrete of the correct strength

will be not much less than the "large amounts of concrete that are unnecessary"

I would stick with your existing engineer.

Johnnyhpipe

If I had a client that was second guessing my every move I would walk away.

trace51

We have already paid the first engineer so any unfairness to them is not a concern. The first engineer is not willing to remain involved and sign off for mortgage etc. (this wasn't something we needed when employing them initially and they now can't take it on).

The second engineer is willing to sign off for the mortgage, but not with the first engineers drawings. Maybe this is to be expected and something we have to accept to move forward.

Tifosi

Calahonda52 wrote: »

OP: What is the incremental cost of the " large amounts of concrete that are unnecessary" and the G versus L footing

The reality is that simple foundations, even those with "large amounts of concrete that are unnecessary" are a much better job than these ones you describe as the additional complexity of their design, when you factor in the cost of executing correctly this complexity for:

1. marking out and digging out the subsoil,
2. setting up the formwork,
3. bending and fixing the rebar
4. pouring and vibrating the concrete of the correct strength

will be not much less than the "large amounts of concrete that are unnecessary"

I would stick with your existing engineer.

The above is probably the best advice, however unless you have rattled his cage too much he should engage with the proposed contractor/s to resolve the query on the foundations.

masculinist

Anyone can build a house with determination, in the same way many of us built a house out of lego as a youngster. Engineering brings a fair bit of maths into this to remove the redundancy and waste when conforming to the architects vision. And giving you a structure which is elegant and efficient. Theres no use using a sledgehammer to crack a nut.

Therefore, provided it's a design you are happy with and serves your needs and provided its all fully insured etc. Then definitely go with the cheapest option . The role of a good engineer is to use minimum materials at minimum cost to achieve the same goal. A side effect might be more environmental with less carbon emissions and waste materials which could be part of your vision or might not be.
Anyone with the skills to save you money deserves the work and the support. Furthermore money doesnt grow on trees. Save it for something useful.