Architects’ fitness for purpose obligation: obligation of means or obligation of result?

Monday 23 October 2023

Credit: Ngampol/Adobe Stock

M Saleh Jaberi

ESK, Tehran

Esmaeil Karimian

ESK, Tehran

There is a consensus among various legal systems that professional service providers have to perform their duties with reasonable skill and care. However, it has been doubted whether their services must be compatible with the intended purpose of their clients. In the construction industry, the work of building contractors ought to fit the intended purpose of owners, and three theories have been proposed regarding the extension of this obligation to architects. Some believe that architects only bear the ‘obligation of means’, which only requires efforts to provide a suitable design without guaranteeing a specific result. A few others, however, believe that architects’ duty is an ‘obligation of result’, which imposes strict liability on architects to provide a design compatible with the intention of their clients. A third theory has also been developed which differentiates between architects’ obligations based on the type of structure. This article looks into these theories and the reasons behind them.


The obligation to use reasonable skill and care in relation to design and the obligation to design a product that is fit for its intended purpose are two general standards of duty recognisable to building contractors and which are imposed on them by statute or by specific agreement. In common law jurisdictions, an implied warranty doctrine has been developed whereby a contractor with a duty to design a building assumes responsibility for ensuring that the result of the design will be reasonably fit for its known required purpose.[1] When an owner requests that a service be ‘fit’ for a particular purpose, it usually refers to the ‘suitability’ of that service for a known or intended purpose.[2] Even when the owner has not informed the contractor about any specific needs, the contractor is still obliged to ensure that the building’s design is suitable for its usual purpose if the contractor is aware of the general purpose of the design.[3]

In the absence of a specific agreement as to the extent of the architect’s responsibilities – because the contract was made orally or poorly drafted – the law implies a duty of exercising the services with ‘reasonable skill and care’.

Despite claims about the contractor’s duty when designing, there are two schools of thought when a professional person, such as an architect, has given advice on the suitability of a particular design or provided a design which has been implemented by the contractor.[4] Some courts and scholars believe that the implied duty of fitness for purpose is not imposed on the architect[5] unless there is a deficiency in the design itself.[6] Therefore, the architect’s obligation regarding the design is categorised as an ‘obligation of means’, which is defined as an obligation to prepare a design with the prudence and diligence of a reasonable person of an expected quality without guaranteeing a specific result. On the other hand, some scholars believe that the nature of the architect’s obligation is an ‘obligation of result’, which imposes strict liability on the architect to achieve a specific purpose; otherwise, the architect will be liable for breach of contract.

The classification of obligations into the obligation of means and the obligation of result is a creation of civil law which is often attributed to French legal academic René Demogue, who first applied the distinction almost a century ago.[7] ‘The obligation of result is simply the obligation of the debtor to attain a predetermined result. The obligation of means or conduct, on the other hand, obliges the debtor “only” to give his or her best effort to reach that result, but does not make him or her responsible solely on the basis of the final outcome’.[8] Imposing either of these obligations would affect the parties’ burden of proof. If a promisor undertakes an obligation of result, they will generally only be discharged from that obligation by providing the agreed result. With an obligation of means, however, the promisee must prove non-compliance by lack of due diligence of the promisor.

Similar concepts of ‘strict liability’ and ‘negligence’ can be identified in the common law. In strict liability cases, it would be enough to show that the defendant has not achieved the promised result even if they were not negligent or at fault;[9] while in negligence cases, the claimant has to show that the defendant was at fault and that, due to this failure, the intended purpose has not been fulfilled. It is interesting that negligence claims against architects have become a routine part of construction disputes and are described as a facet of the perceived tort liability crisis confronting professionals.[10]

In this article, these two opposing opinions relating to the nature of an architect’s obligation are examined, and the reasoning behind each of them is considered to determine the scope of architects’ liability regarding the suitability of a building for the owners’ purposes.

Architects’ obligation of means

Signing a contract is a starting point for an architect’s professional relationship with a client and defines the scope of their respective obligations. It is particularly important for architects to define the scope of their services accurately and specify the quality of the final design that will be provided to the client in order to avoid future disputes. Therefore, the parties’ contract should clearly determine whether or not the architect is responsible for supervising the implementation of the design or whether the architect provides any type of guarantee regarding their design.

In the absence of a specific agreement as to the extent of the architect’s responsibilities – because the contract was made orally or poorly drafted – the law implies a duty of exercising the services with ‘reasonable skill and care’.[11] In other words, when a person is appointed to act in a professional capacity, he or she assumes an obligation to exercise a degree of skill and care which is to be expected of a reasonably competent member of the profession.[12] However, it has been doubted whether an obligation to achieve a particular result is also implied in such professional contracts or whether the architect’s responsibility is limited to the obligation of means.

In Hawkins v Chrysler (UK) Ltd,[13] Dillon LJ stated:

‘The general position […] is that a professional man who is called in to advise is bound, and impliedly undertakes, to use reasonable skill and care in advising, but is not responsible for providing a perfect result or a perfect building.’[14]

Similarly, in Greaves & Co (Contractors) Ltd v Baynham Meikle & Partners,[15] Lord Denning MR observed that:

‘Apply this to the employment of a professional man. The law does not usually imply a warranty that he will achieve the desired result, but only a term that he will use reasonable care and skill. The surgeon does not warrant that he will cure the patient. Nor does the solicitor warrant that he will win the case.’[16]

Therefore, it has been observed on many occasions that those who provide professional services, such as architects and engineers, do not guarantee that they will produce the desired result unless the parties’ agreement contains a guarantee that a design will work in a certain way or the building will be constructed at a certain cost.[17]

An architect may warrant that a design will be fit for the purpose of the client or that the design will be compatible with a specific standard, although it has no control over the actual implementation of the design.[18] It is also possible that the duty of the architect includes other obligations, such as supervising the implementation of the design, which, together with other facts of a case, may lead to an obligation of result.[19] However, in the absence of any specific term or circumstances to infer such an undertaking, ‘English courts have been reluctant to construe the contracts of architects (or other professional persons) as warranting absolute results’.[20]

The US courts have applied a similar theory since the 19th century. In the case of Coombs v Beede,[21] the Supreme Court of Maine said:

‘The undertaking of an architect implies that he possesses skill and ability, including taste, sufficient to enable him to perform the required services at least ordinarily and reasonably well; and that he will exercise and apply in the given case his skill and ability, his judgment and taste, reasonably and without neglect. But the undertaking does not imply or warrant a satisfactory result.’[22]

has been observed on many occasions that those who provide professional services, such as architects and engineers, do not guarantee that they will produce the desired result

This argument has been followed by many other US courts. Even where an architect has a supervisory duty, he was not considered liable for achieving a desirable result.[23] The handful of courts that imposed a warranty on designers have been censured as being poor precedents and reaching a conclusion through misinterpretation and faulty analysis.[24] In 2015, the Appellate Court of Illinois, after having considered many previous cases, concluded the following:

‘Other jurisdictions that have addressed this issue have also concluded that a design professional may not be sued under an implied warranty theory for providing professional services. Furthermore, the principle that an architect does not warrant or guarantee perfection in his or her plans and specifications is a long standing principle.’[25]

The Australian Consumer Law, which guarantees that services and any products resulting from the services are fit for purpose and achieve the intended result, made an exception for architects by stating that ‘This section does not apply to a supply of services of a professional nature by a qualified architect or engineer’.[26] The Australian common law seems to approve this approach by limiting the architects’ duty to use reasonable skill and care. The Supreme Court of Queensland held in Orlit Pty Ltd v JF & P Consulting Engineering Pty Ltd[27] that the consultant did no more than contract to provide its professional services in respect of some aspects of a much larger project, as opposed to contracting to achieve a specific result.

Architects’ obligation of result

The theory of strict liability seems to have developed in common law jurisdictions in the 1950s and early 1960s as a result of a public policy to protect consumers from defective products.[28] The stated reason for holding manufacturers liable for defective products irrespective of whether there was any negligence was that manufacturers are in the best position to control and eliminate the risks posed by defective products.[29] Another reason for imposing strict liability in tort law is to reduce the time and costs of proving negligence. Showing how carefully the defendant acted on a particular occasion often requires more cost and time than showing that the defendant is liable because of an injury or defect caused by their action. When strict liability is imposed, there is no need to provide evidence of compliance or violation of customary practice. Moreover, there is regularly no need to use expert testimony, and there is no need to demonstrate the violation of an applicable statute. Furthermore, a person who is threatened with strict liability has a greater incentive to avoid liability and insure or otherwise broadly distribute the costs of non-negligently caused accidents. Strict liability is also compatible with the ‘benefit’ theory – that is, those who benefit from engaging in an activity should rightly bear the liabilities associated with the activity.[30]

The aforementioned vindications extend to professional service providers,[31] and a few scholars, mainly from civil law countries, believe that architects bear strict liability, which means their work has to achieve the intended result; otherwise, they breach their obligation.[32] Generally speaking, ‘Dutch and English architects are under an overall obligation of means regarding their design duties. Belgian and German architects, however, are strictly liable for some of their obligations. And French architects are predominantly under an obligation of result when they perform their obligations towards the client under the design contract’.[33]

According to one civil law commentator, ‘[t]he obligation of engineering and architecture professions towards the employer is the obligation of result. It means that proving the observance of the necessary precautions and effort to achieve the desired purpose is not enough [...] In this profession, contrary to what was said regarding the error of a doctor, it is possible to guarantee the result and predict the obstacles. The foundation of parties’ intention is to achieve the desired goal, not to strive towards it [...] In a lawsuit between the employer and the architect, it is sufficient to prove that the desired result was not achieved, and there is no need for the claimant to attribute a specific fault to the defendant’.[34]

Accordingly, whether the obligation of means or obligation of result is imposed depends on the degree of probability of achieving the intended purpose. In other words, some civil law courts consider the extent to which the realisation of the result is plausible.[35] When the possibility of achieving a specific result outweighs the uncertainty of fulfilling an obligation, it is likely that the court will impose strict liability on the promisor of the contract. Since it is believed that the architect is in a better position to predict and eschew the construction obstacles, it is reasonable for the client to expect the design prepared by the architect to have a certain degree of buildability. Therefore, there is a belief that the architect undertakes an obligation of result and that their design has to fit the intended purpose of the client.

The Supreme Court of Kansas confirmed this theory in Tamarac Dev Co v Delamater, Freund Assocs.[36] The court said:

‘The work performed by architects and engineers is an exact science; that performed by doctors and lawyers is not. A person who contracts with an architect or engineer for a building of a certain size and elevation has a right to expect an exact result.’[37]

On the other hand, the predictability of design obstacles by architects has been criticised by the Supreme Court of Minnesota in City of Mounds View v Walijarvi.[38] The Court said:

‘If every facet of structural design consisted of little more than the mechanical application of immutable physical principles, we could accept the rule of strict liability which the City proposes. But even in the present state of relative technological enlightenment, the keenest engineering minds can err in their most searching assessment of the natural factors which determine whether structural components will adequately serve their intended purpose. Until the random element is eliminated in the application of architectural sciences, we think it fairer that the purchaser of the architect’s services bear the risk of such unforeseeable difficulties.’[39]

Among these different opinions, a third theory has been put forth, which proposes that the responsibility of the architect varies depending on the type of structure. Thus, the architect bears an obligation of means in complex buildings and an obligation of result in routine structures.

Architects’ dichotomous obligation

According to this dovish opinion, the nature of an architect’s obligation depends on the type of building they are going to design. In urban construction, it is reasonable to expect the architect to guarantee the result because there is no new or complex problem that prevents the achievement of the desired result. In complicated and modern designs, such as the design of marine platforms, suspension bridges, or oil extraction facilities, on the other hand, there is a possibility of making mistakes even by the best designers, so assuming strict liability for designing such structures would not be fair.[40]

Lord Erle J corroborated this point of view in the case of Turner v Garland,[41] in which the negligence of an architect was claimed because of their recommendation to use a new method of roof construction, which was considerably cheaper than conventional methods. He stated:

‘You should bear in mind that if the building is of an ordinary description, in which [the architect] has had abundance of experience, and it proved a failure, this is an evidence of want of skill or attention. But if out of ordinary course, and you employ him about a novel thing, about which he has had little experience, if it has not had the test of experience, failure may be consistent with skill. The history of all great improvements shows failure of those who embark in them; this may account for the defect of roof.’[42]

This opinion seems fair because it secures the interests of clients, and, at the same time, it adjusts the obligation of the architect in accordance with the actual conditions of each construction project. However, the novelty of a design would not be adequate to release the architect from their obligation to achieve the desired purpose because the architect has another duty (ie, to inform the client of expected problems and risks). As Judge Newey QC observed in Victoria University of Manchester v Hugh Wilson & Womersley:[43]

‘I think, however, that architects who are venturing into the untried or little tried would be wise to warn their clients specifically of what they are doing and to obtain their express approval.’[44]

Therefore, it is suggested that the courts answer three major questions to determine whether the architect’s work should achieve the intended result or if the architect undertakes only the obligation of means: (1) Did the loss or failure occur because of the novelty of the design? (2) Did the novelty lead to a risk that could have been anticipated? (3) If so, was the client given an adequate warning about that risk?[45] Where the architect’s design has not achieved the intended purpose of the client, the architect can avoid liability if the design was novel and if the architect duly warned the client about the possible risks of implementing the design.

has been observed on many occasions that those who provide professional services, such as architects and engineers, do not guarantee that they will produce the desired result


When a contractor or an organisation combines design and construction functions, the courts have found that the contractor warrants the fitness of their product for the client’s purpose, provided that the client relies on the furnished design.[46] Nevertheless, in the traditional construction project delivery method, there is no overlap between design and construction, so the duty of architects should be considered separately from that of contractors. Therefore, it has been doubted whether architects also bear the ‘fitness for purpose’ responsibility or whether they only undertake the duty of using reasonable skill and care when preparing designs.

The fitness for purpose obligation can be specifically agreed upon in design contracts or consultancy agreements to ensure that whatever is being designed or supplied is suitable for the intended purpose of the client. However, when there is no such explicit clause in the parties’ contract, courts and legal scholars have provided three opinions regarding the imposition of strict liability on the architect to provide plans and specifications which are compatible with the intended purpose of its client in the construction project. Under civil law, the liability under such contracts will be set between the ‘obligation of result’ (the obligation of achieving a certain result) and the ‘obligation of means’ (the obligation of dedicating a certain amount of resources to achieve a particular result).[47]

Based on the first theory, the responsibility of an architect is similar to that of a lawyer or a physician. If the architect has the necessary skills and knowledge and uses their best judgement in exercising those skills and knowledge, they have satisfied their legal requirements. The architect is not a warrantor of their plans and specifications, and their work may have defects when implemented by a contractor, even if the architect exercised the reasonable skill required.[48]

On the other hand, a few courts and scholars believe that architects can predict all obstacles and possible defects of their designs when implemented. The nature of their work is an ‘exact science’, which makes them different from lawyers and doctors. Therefore, their clients are entitled to expect a design that is fit for the intended purpose, and architects should undertake absolute liability if their design is unsuitable. Alternatively, a third theory was developed which holds that the responsibility of the architect varies according to the type of structure. If the client requests a design for a simple and common structure, due to the architect’s ability to predict possible defects and the routineness of the design implementation, the responsibility of the architect is absolute, and they guarantee that the result is fit for the intended purpose of the client. However, if the requested design is novel and complex, it is unreasonable to expect the architect to guarantee the result and bear strict liability, provided that the architect warns the client of any potential risks and problems.


[1] Greaves & Co (Contractors) Ltd v Baynham Meikle & Partners (1975) 1 WLR 1095. Independent Broadcasting Authority v EMI Electronics (1980) 14 BLR 1 at 48: ‘In the absence of any term (express or to be implied) negativing the obligation, one who contracts to design an article for a purpose made known to him undertakes that the design is reasonably fit for the purpose.’ John Lelliott (Contracts) Ltd v Byrne Bros (Formwork) Ltd (1992), 31 Con LR 89: (Held: Where a party agrees to supply a structure for a particular purpose made known to him the court will readily imply a term that the structure be fit for its purpose).

[2] Maersk Oil UK Ltd v Dresser-Rand (UK) Ltd (2007) EWHC 752 (TCC) at [68]–[69].

[3] This is the result of exercising an ordinary degree of skill and care in undertaking the necessary design work. See: Benfield (Trading As Autoroute Circuits) v Life Racing Ltd (2007) EWHC 1505 (TCC). It should be noted that the standard ‘Fitness for Purpose’ will only be considered in relation to the works designed by the contractor and does not include the designs made by the employer. On the other hand, where no purposes are so defined and described, the works shall be fit for their ordinary purposes; see eg, FIDIC Silver Book (2017 edition) section 4.1.

[4] Engineers who design and supervise construction face the same issues discussed in this article. Although both architects and engineers perform design functions, architects are generally employed in residential or commercial construction, whereas engineers are generally employed on industrial and public utility projects.

[5] George Hawkins v Chrysler (UK) Ltd and Burne Associates (1982), 38 BLR 36.

[6] Julian Bailey, Construction Law (2nd edn, Routledge, 2016) p 197.

[7] R Demogue, Traité des obligations en général: Tome V, Paris, Rousseau, 1925, 1237.

[8] Nico Moons, The Right to housing in law and society (1st edn, Routledge, 2018) p 137.

[9] Implied warranty is a term that is often used instead of strict liability. When the law imposes implied warranty, the plaintiff need not prove that a seller was negligent in the manufacture or sale of the product in order to state a cause of action. Plaintiff need only prove that the product was of bad quality ie, not fit for the ordinary purpose for which it was sold. See: James J White and Robert S Summers, Handbook of the Law Under the Uniform Commercial Code (West Publishing Company, 1972) s 9-6.

[10] Matthew S Steffey, ‘Negligence, contract, and architects’ liability for economic loss’, 82(3) 1993, Kentucky Law Journal, 659-660.

[11] Cooper v Australian Electric Company Ltd, (1922) 25 WALR 66. Henderson v Merrett Syndicates Ltd (1995) 2 AC 145 at 193-194: ‘It is however my understanding that by the law in this country contracts for services do contain an implied promise to exercise reasonable care (and skill) in the performance of the relevant services.’ Astley v Austrust Ltd (1999) HCA 6, at 21-23. For statutory obligation see: Supply of Goods and Services Act 1982 (UK) s 13; Consumer Rights Act 2015 (UK) s 49(1); Australian Consumer Law, s 60.

[12] Platform Funding Ltd v Bank of Scotland Plc. (Formerly Halifax Plc) (2009) QB 426.

[13] 537 (1986) 38 BLR 36.

[14] Hawkins v Chrysler (UK) Ltd, 537 (1986) 38 BLR 36 at 53.

[15] (1975) 3 All ER 99.

[16] Greaves, n 15, at 103-104.

[17] Platform Funding, n 12, at 17. See also: Holland Hannen & Cubitts (Northern) Ltd v WHTSO (1985) 35 BLR 1.

[18] Costain Ltd v Charles Haswell & Partners Ltd (2009) EWHC B25 (TCC) at 55.

[19] Tesco Stores Ltd v Norman Hitchcock Partnership Ltd [1997] 56 Con LR 42.

[20] Ben Patten and Hugh Saunders, Professional Negligence in Construction (2nd edn, Routledge, 2020) p 12.

[21] 89 Me 187 (56 Am St Rep 406) 1896.

[22] Coombs, n 21. At 188–189.

[23] Gravely v Providence Partnership, 549 F 2d 958 (4th Cir 1977): ‘the ordinary engagement to supervise does not rise to the force of a warranty; the architect is only charged with the duty to exercise reasonable care, technical skill and ability in the performance of his contract [citation omitted]’.

[24] Jeff Sobel, ‘Architect Tort Liability in Preparation of Plans and Specifications’, 55(5) 1967, California Law Review, 1383-1384.

[25] Bd of Managers of Park Point at Wheeling Condo Assn v Park Point at Wheeling, LLC, 48 N E 3d 1250, 2015 Ill App 123452 (Ill App Ct 2015) at 1257.

[26] The Australian Consumer Law (2010), s 61.

[27] (1995) 11 BCL 260.

[28] Sheila L Birnbaum, ‘Unmasking the Test for Design Defect: From Negligence [to Warranty] to Strict Liability to Negligence’, 33(3) 1980, Vanderbilt Law Review, 593 at 596.

[29] Sheila L Birnbaum, n 28, 526.

[30] Kenneth S Abraham, ‘Strict Liability in Negligence’, 61(2) 2012, DePaul Law Review, 271.

[31] Cronin v JBE Olson Corp, 8 Cal 3d 121, 1972: ‘A defect may emerge from the mind of the designer as well as from the hand of the workman.’ See also Hyman v Gordon, 35 Cal App 3d 769, 1973.

[32] Stéphanie van Gulijk, European Architect Law: Towards a New Design (Maklu Publishers, 2009) 120.

[33] Stéphanie van Gulijk, n 32, at 120.

[34] Nasser Katouzian, Obligations Outside the Contract (Civil Liability), (vol 1, Tehran University Press, 2008) p 176.

[35] Nico Moons, n 8, p 138.

[36] 234 Kan 618, 675 P 2d 361 (Kan 1984).

[37] Tamarac, n 36, at 622. Supreme Court of South Carolina held in Hill v Polar Pantries, 219 SC 263, 271 (SC 1951) ‘if a party furnishes specifications and plans for a contractor to follow in a construction job, he thereby impliedly warrants their sufficiency for the purpose in view’. See also: Beachwalk Villas Cond v Martin, 406 S E 2d 372 (SC 1991); Bloomsburg Mills v Sordoni Const Co, 164 A 2d 201 (Pa 1960).

[38] 263 NW 2d 420 (Minn 1978).

[39] City of Mounds View, n 38 at 424.

[40] Seyed Sadegh Kashani, Civil Liability Arising from Design in the Construction Industry (1st edn, Legal Studies and Research Institute of Shahr Danesh, 2013) p 104.

[41] (1853) Hudson’s Building Contracts, (4th edn, 1914) p 1.

[42] Turner, n 41, at 2. See also: Major v Leary, 241 App Div 606, (NY App Div 1934) in which the plaintiffs engaged an architect to draw plans for an elaborate and pretentious country residence with unusual design. The court held that some mistakes in the plans and specifications are bound to be in an undertaking of the nature and scope of presented design, since the law does not expect or require absolute perfection.

[43] (1984) 2 Con LR 43.

[44] Victoria University of Manchester, n 43, at 74. In Try Build Ltd v Invicta Leisure (Tennis) Ltd (1997) 71 Con LR 141, novel features of design did not help the engineers and they were found to have been negligent in failing to check and warn of deficiencies in the designs prepared by specialist sub-contractors. See also: Pullen v Gutteridge Haskins & Davey Pty Ltd (1993) 1 VR 27 (App Div).

[45] Ben Patten and Hugh Saunders, n 20, p 94.

[46] Note, ‘Architectural Malpractice: A Contract Based Approach’, 92(5) 1979, Harvard Law Review, 1093.

[47] Edwina Elena Udrescu, ‘Fitness for Purpose Obligation in Construction Contracts’, 12(1) 2018, Rom Arb J 30.

[48] Gibson B Witherspoon, ‘When Is an Architect Liable?’ 48(4) 1962, American Bar Association Journal, 322.

Dr M Saleh Jaberi is a partner at ESK Law Firm in Tehran and author of the book Construction Law and is actively involved in construction contracts. He can be contacted at jaberi@esklawfirm.com.

Mr Esmaeil Karimian is managing partner of ESK Law Firm and can be contacted at karimian@esklawfirm.com.